Home

falling weight deflectometer relative calibration analysis

Contents

1. FOR 1 7 Avg NX Set STRSCNZ Avg PRINT 2 USING t1 Avg NX MeanLoad NX MeanBySet 1 NX MeanBySet 2 NX MeanBySet 3 NX MeanBySet 4 NX MeanBySet 5 MeanBySet 6 NX MeanBySet 7 NA MeanSets NX NEXT NX PRINT Z2 PRINT 2 PRINT 2 Overall Statistics PRINT 2 PRINT Z2 Load Df1 Df 0 3 0 4 0 5 0 6 0 7 Df1 7 PRINT 89 5 1 eec SORES madoe 55 5 eede 155446 PRINT 2 USING t2 Average MeanAllLoad MeanDef 1 2 3 MeanDef 4 MearDef 5 MeanDef 6 MeanDef 7 MeanAl PRINT 2 USING t3 Std StdDevAllLoad StdDevDef 1 StdDevDef 2 StdDevDef 3 StdDevDef 4 Stdewef 5 Std DevDef 6 Std DevDef 7 StdDevAllDef PRINT 2 USING t4 COV X CVAllLoad CVDef 1 5 2 CVDef 3 CVDef 4 CWef 5 6 CVDef 7 PRINT 42 PRINT 2 PRINT 42 Position in Stand PRINT 42 1 2 3 4 5 6 PRINT 2 sees socos 0 4 PRINT 2 USING t5 Avg Df 1 MeanPos 2 MeanPos 3 MeanPos 4 MeanPos 5 MeanPos 6 MeanPos 7 PRINT 2 USING t Std Dev StdDevPos 1 StdDevPos 2 StdDevPos 3 StdDevPos 4 StdDevPos 5 StdDevPos 6 StdDevPos 7 PRINT 2 USING 7 COV
2. gt L 1434 512 512 515 513 512 512 512 22784 20 16 20 15 20 26 20 18 20 17 20 16 20 16 1407 508 510 510 510 510 509 509 22360 20 00 20 07 20 09 20 06 20 09 20 03 20 04 1381 505 504 506 505 505 504 505 21936 19 88 19 86 19 93 19 90 19 87 19 86 19 88 1380 503 502 506 503 502 503 503 21928 19 79 19 77 19 93 19 82 19 78 19 81 19 80 503 505 503 504 503 503 21696 19 79 19 81 19 88 19 82 19 82 19 81 19 80 Figure 1 Excerpt from a Dynatest FWD relative calibration data block Gains Table The relative gain settings for a Dynatest FWD are multipliers used to refine the deflection sensor calibration The manufacturer generally sets these gains to 1 000 The FWD operating program allows the user to adjust these gain settings in the range 0 980 to 1 020 The primary result of the analysis on the relative calibration test data is the computation of new deflection sensor gain settings so that all sensors produce equivalent results The determination of the need to change gain settings is based on the amount of difference between the sensor responses This information is provided by the FWDCAL program in the gains table The gains table contains the following information Sensor Number This is the sensor number read from the header block This number should correspond to the position or channel that the sensor is connected to on the FWD Sensor Serial Number Existing Gain Factor Means Ratio New Relative Gain FWDC
3. 9 IF NOT ErrFlagX THEN path OK CALL CDir CurrPath ErrFlag t switch back to curr dir ELSE path not OK REDIM PUText 2 PUText 1 Error occurred switching to FPath PUText 2 May not be a valid path Please try again CALL PopupError ExitCode 0 FPath OldPath END IF END IF END IF IF FPath lt gt AND RIGHT FPath 1 lt gt X THEN FPath FPath X LOCATE 7 37 PRINT FPath CASE 2 DO 94 ZP CALL GetString 10 60 1 2P L 0 0 ExitCodeX ZP UCASES ZP SELECT CASE 2P CASE ShowFiles FPath v NumMatchs FCount ShowFiles IF NumMatchs gt 0 THEN CALL DisplayFileNames NumMatchsX ShowFiles FPath file Ext ExitCode 0 WFile file Ext ELSE REDIM PUText 1 PUText 1 No files found matching ShowFiles CALL PopupError ZP END IF CASE on CASE ELSE REDIM PUText 1 PUText 1 Please choose a Y or only try again CALL PopupError ExitCodeX 0 END SELECT IF ExitCodeX lt gt 0 THEN EXIT DO LOOP CASE 3 DO OldwFile CALL GetString 13 34 12 MFile L 0 0 ExitCodeX WFileS LTRIMS RTRIMS UCASES WFile LEN WFile FOR VV 1 TO LF chk ASC MIDS WFile VV 15 IF chk 32 THEN REDIM PUText 1 PUText 1 SPACES ARE NOT ALLOWED IN FILE NAMES CALL PopupError WFile OldWFilesS ExitCodeX 0 EXIT FOR END IF NEXT
4. SumTotal 0 TotalSs 0 FOR iX 1 TO NumSensorsX 71 1 0 MeanDefZ iX 0 1 0 MeanSet 1 0 FOR J 1 TO NumSets MeanBySet i 0 NEXT J NEXT 1 55515454334 Compute main statistics for the analysis whe kk dkk kkk d kkk k FOR iX 1 TO NumSensors FOR J 1 TO NumPositions FOR KX 1 TO NumSets FOR LX 1 TO NumRepsX SumTotal SumTotal DefData iX 4 K 1 TotalSS TotalSS DefData i K L 2 1 Tis iX DefData i J 1 sSumTi i SSumTi i 14 4 5 1 2 Tj J Tj8 JX 1 JA 1 SSumT j J SSumTj J DefData iX 4 1 2 Tk K Tk K DefData iX 2 1 Tij Ci 4 Tij ciz 4 DefData l 1 JA K 1 Tik i Tiki iX DefData 1 4 LX Tjk J Tjk J 1 1 Tijk Ci 4 K 4 4 KA LX NEXT LX NEXT NEXT J NEXT 1 SumTi 0 SumT j 0 SumTk 0 SumTij 0 SumT1k 0 SumT jk 0 FOR 1 1 TO NumSensors SumTi SumTi TiZ iX 2 SumT j SumTj 2 SumTk Tk i 2 FOR J 1 TO NumPositionsA SumTij SumTij Tij Ci 4 2 SumTik SumTik 1 4 2 SumT jk SumTjk Tjk Ci 4 2 NEXT J NEXT 1 t Yelesedee dede dede de de
5. 224 CASE 30 active sequence drops 225 Posit INSTR LineData 226 ActiveDrops Posit 1 227 IF ActiveDrops lt 46 THEN CALL BadFile 228 CASE 33 peaks stored 229 CheckText LEFT LineData ActiveDropsA 230 InitNumPeaksX InCount2X CheckText 231 Numrops InitNumPeaks X NumSetsA 232 IF InitNumPeaks MOD NumDropsX gt 0 THEN CALL BadFile 233 END SELECT 234 END SUB 235 236 237 238 259 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 SUB Cochran Cochran s test to determine significance of variance between sensors set up Vdef Mean Sensor for sorting DIM Temp 1 2 Vdef 7 2 FOR 54 1 7 Vdef S 1 StdDewWef S 2 Vdef S 2 5 5 SORT FOR Iter 1 TO 7 FOR 5 1 6 IF Vdef S 1 1 gt Vdef S 1 THEN Temp 1 1 Vdef S 1 1 1 2 Vdef S 1 2 Vdef S 1 1 Vdef S 1 Vdef S 1 2 Vdef S 2 Vdef SX 1 1 1 Vdef S 2 1 2 END IF NEXT NEXT Iter BigVarDev Vdef 1 1 BigDef Vdef 1 2 Sum all Means FOR 1107 SumVarDev SumVarDev StdDevDef MX 2 NEXT MX G BigVarDev SumVarDev IF 6 gt Galph THEN ProblemExist 1 END SUB FWDCAL2 BAS March 28 1992 Page 8 FWDCAL2 BAS March 28 1992 9 SUB DisplayCopyright STATIC SCREEN 0 WIDTH 80 CLS PRINT PRINT PRINT
6. Average deflection for sensor i means ratio for each sensor 15 R E 3 i where R The means ratio of sensor i The new relative gain factor is computed as Creo Fi 4 where The new relative gain factor for sensor i The existing relative gain factor for sensor i Guy The values of the means ratio are compared against a tolerance range of 1 000 0 003 If the means ratio falis outside of this range a YES is displayed in the out of limit tolerance column in the gains table The new relative gains are compared against a range from 0 980 to 1 020 which corresponds to the manufacturer s specified 2 tolerance If a new relative gain value falls outside of this range a YES is displayed in the out of limit 2 range column The other messages displayed by the program are discussed in the program output portion of this document FWDCAL Version 2 Program Manual February 1992 It is important to note that the geophones on a Dynatest FWD must be in the position indicated in the FWD operating software If the position of a geophone is switched on the FWD a change must be made in the geophone set up table in the operating program Otherwise the program will use the wrong gain and amplification factors for the geophone Latin Square ANOVA The SHRP relative calibration procedure was designed in such a way that a statistical analysis of variance ANOVA procedure could be run on the results The pur
7. CASE PRINT Nothing is significant Gain adjustments are indicated A repeat calibration PRINT is required to confirm the need for adjustments CASE PRINT The gain ratios and the statistical results indicate that gain adjustments 17 695 694 695 FWDCAL2 BAS March 28 1992 Page 18 PRINT needed A repeat calibration is required to confirm the need for gain PRINT adjustments CASE NNY PRINT Gain adjustments are indicated Stand position is statistically PRINT significant at the 5X level A repeat calibration is required to confirm PRINT the need for gain adjustments Care should be taken to ensure that the PRINT geophone bases are clean firmly seated and that the stand is held PRINT vertically with moderate downward pressure CASE NYY PRINT Gain adjustments are indicated Sensor and Stand position are statistically PRINT significant at the 5X level A repeat calibration is required to confirm PRINT the need for gain adjustments Care should taken to ensure that the PRINT geophone bases clean firmly seated and that the stand is held PRINT vertically with moderate downward pressure CASE ELSE END SELECT ELSE SELECT CASE LSAM CASE YNN PRINT No gain adjustments are indicated but drop set is statistically significant PRINT at the 5X Level This can be due to warming of the buffers or consolidation PRINT of pavement material
8. PRINT PRINT PRINT LOCATE 10 LOCATE 12 LOCATE 15 LOCATE 20 LOCATE 21 LOCATE 23 SLEEP 4 35 20 10 12 13 PRINT PRINT PRINT PRINT PRINT PRINT CALL NormalColor CALL ClearBuf END SUB FWD Relative Calibration Analysis Software Version 2 0 Strategic Highway Research Program SHRP Support material Copyright c 1989 PCS Law Engineering Inc Additional material Copyright c 1988 Crescent Software Enhancements by Nichols Consulting Engineers Chtd 1992 285 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 502 303 304 305 306 307 508 509 310 311 312 513 314 315 316 317 518 319 520 321 322 325 324 325 326 327 328 329 330 331 332 333 334 FWDCAL2 BAS March 28 1992 Page 10 SUB FileToScreen STATIC FTS Yt WindowTypeX 1 CLS WFile file OExt CALL NormalColor LOCATE 7 7 PRINT Output Path and File Name LOCATE 7 37 PRINT FPath WFile LOCATE 13 7 PRINT Display calibration results on screen CALL HiliteColor LOCATE 13 50 PRINT 5 CALL NormalColor DO OldFTS FTS CALL GetString 13 50 1 FTS L 0 0 ExitCodeX FTS 5 5 SELECT CASE 5 CASE Yt CALL NormatColor CLS CALL GainsPagel Img PgDn to ANOVA Table Esc to exit results screens Img Img 2 PRINT Img 00 aS INKEY LOOP WHILE a IF LEN a 2 THEN a RIGH
9. custom built reference load cell 300 mm diameter 40 000 lbs capacity connecting cable Vishay to load cell 19 SHRP FWD CALIBRATION PROTOCOL April 1993 Note Drawings of each of the special items of equipment and cabling diagrams are available from the Long Term Pavement Performance LTPP Division at the Federal Highway Administration Turner Fairbank Highway Research Center McLean Virginia IBM PC XT or PC AT or compatible computer recommended IBM PS 2 computer acceptable Configuration e 80386 processor or higher e 25 MHz or faster processor speed co processor if applicable megabyte or more RAM 100 megabyte or more hard drive an 8 bit expansion slot for the MetraByte board Monitor e Color monitor monochrome not recommended e VGA recommended EGA acceptable Graphics Printer Laser printer recommended dot matrix acceptable but very slow Where both recommended and acceptable options are given in the above specifications an effort has been made in the software development to accommodate both alternatives However since most of the testing has been done on computer hardware meeting the recommended specifications installation of the calibration station will go more smoothly if those specifications are met A demonstration version of the FWDREFCL software is available from the LTPP Division in the Federal Highway Administration located at the Turner Fairbank Highway Research
10. Day MID FileDate 5 2 MDY Month Year 4 1 0 Jnum2 0 FOR 1 1 TO NumSensors ABS 1 MeansRat SC 1 gt 003 THEN TOL S 1 YES Jnumi Jnumi 1 ELSE TOL iX NO END IF IF 1 NewGain SC 1 gt 02 THEN RANS 1 YES Jnum2 Jnum2 1 ELSE 1 NO END IF NEXT 1 8 de de ee ee oe e de e e ee deed e k k fe jede dede e Geophone Calibration dedek de de je e de de de de de de he dede dee PRINT 42 SPC 18 SHRP FWD Relative Calibration Gains Table PRINT 2 FWD SN FWDSN SPC 37 Calibration Date MDY PRINT 42 Data File Name file Ext SPC 32 Data Set SCA of 1 SetCount PRINT 2 Operator Operators PRINT 2 PRINT 2 Sensor Existing Means New Out of Limit PRINT 2 Sensor S N Gain Factor Ratio Relative Gain Tolerance 2 Range PRINT 2 185 HHH HHH VM FOR SX 1 TO NumSensorsX PRINT 2 USING 8 SX SerialNum S RelGain S MeansRat SC 5 NewGain SC 5 5 NEXT SX PRINT 2 IF Jnum1X gt 0 THEN PRINT 2 Warning At least one sensor is outside the tolerance limit PRINT 42 Verify these results with additional tests END IF IF Jnum2X gt 0 THEN PRINT 42 Warning At least one sensor is outside the 2 range limit PRINT 42 Notify Supervising Engin
11. Marshall R Thompson University of Illinois Kenneth R Wardlaw Exxon Chemical Corporation Marcus Williams Zachry Company Liaisons Albert J Bush USAE Waterways Experiment Station Louis M Papet Federal Highway Administration John P Hallin Federal Highway Administration Ted Ferragut Federal Highway Administration Frank R McCullagh Transportation Research Board Expert Task Group Paul D Anderson Mountainview Geotechnical Ltd Robert C Briggs Texas Department of Transportation Albert J Bush USAE Waterways Experimental Station Billy G Connor Alaska Department of Transportation William Edwards Ohio Department of Transportation John P Hallin Federal Highway Administration Frank L Holman Jr Alabama Highway Department William J Kenis Federal Highway Administration Joe P Mahoney University of Washington Larry A Scofield Arizona Transportation Research Center Richard N Stubstad Dynatest Consulting Inc Marshall R Thompson University of Illinois Per Ullidtz Technical University of Denmark Jacob Uzan Texas A amp M University Wes Yang New York State Department of Transportation
12. Output Screen 3 Gain Change Instructions Output Screen 4 Average New Gain Factors Funcion dove Anomalous ReSsulfs rh eh ey ees we dw ei a Technical ASSIStance Appendix A SHRP FWD Calibration Protocol Appendix B FWDCAL 2 0 Program Listing Appendix C Latin Square Analysis of Variance ANOVA af Abstract Non destructive deflection testing with Falling Weight Deflectometers FWDs is a critical element of the pavement monitoring effort for the Long Term Pavement Performance LTPP test sections of the Strategic Highway Research Program Data obtained through this testing serves as the primary mechanism for assessing structural conditions within each LTPP test section For the LTPP deflection data to serve its intended purpose the deflection testing must be conducted consistently and with accurately calibrated FWDs This report documents the FWDCAL software which was developed to help ensure that the latter need is met SHRP FWD testing procedures require that the FWDs used be calibrated on a regular basis One aspect of this requirement is monthly relative calibration of the FWD deflection measurement system This process involves stacking the deflection sensors one above another in a special stand so that all will simultaneously measure the deflection of the pavement at the same point By rotating the sensors through the positions in the s
13. good security for calibration equipment Test pad e 15 feet by 15 feet with an 5 Zoot wide clear zone around perimeter for maneuvering WDSs and the reference data acquisition system smooth crack free portland cement concrete surface modest amount of hairline cracking is permissible Should the test pad develop cracks which are visibly open 1 16 inch or more it should be replaced e isolated by impregnated felt bond breaker sawed and caulked joint from the area where the concrete inertial block supporting the aluminum reference beam will rest slab deflection of at least 16 mils due to 16 000 load at the position of the deflection sensor holder when the FWD is in the specified position for calibration The sensor holder should be located not closer than two feet from the edge of the test pad but it 1s not required nor is it possible that the test pad should deflect uniformly across the entire area of the pad Because the inertial block supporting the aluminum reference be must be placed adjacent to but not on the calibration test pad the maximum possible distance from the sensor holder to the edge of the test pad will be about five feet Note Fatigue calculations indicate that acceptable fatigue life can be achieved with a 5 inch thick portland cement concrete slab resting on an 8 inch open graded crushed stone base A layer of filter fabric should be placed below the base to protect it from intrusion of subg
14. istart of history block found a comment found subsection id normal processing LineData B 29 FWOCAL2 BAS March 28 1992 Page 29 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 FWDCAL2 BAS March 28 1992 Page 30 SUB ReplaceSensor IF RepSens lt 1 OR RepSens gt 7 THEN EXIT SUB END IF MeanRepDef SumTotal Ti RepSens NumSensors 1 NumSensorsA NumReps 5 1 TO NumSensors amp MeansRat SC SX MeanRepDef 54 NewGain SC SX MeansRat SC SX RelGain S NEXT S IF ABS 1 MeansRat SC RepSens gt 003 THEN repm1 Means Ratio for REPLACED Sensor No STRS SerialNum RepSens is outside the tolerance range repm2 New Relative Gain for REPLACED Sensor No STR SerialNumX RepSensX is ELSE repmi Means Ratio for REPLACED Sensor No STR SerialNumX RepSensX is within the tolerance range repm2 New Relative Gain for REPLACED Sensor No STR SerialNumX RepSensX is END IF END SUB 30 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 FWDCAL2 BAS SUB SelectAnalysis CLS Choice 1 IF SetCount gt 1 THEN 3 END
15. 628 629 630 SUB GetSensorNum CLS Choice 1 DO REDIM Item NumSensors amp 2 TitleS Select Geophone Replaced FOR 1 1 TO NumSensorsX Item iX Sensor No STR SerialNumA iX NEXT iX Item 8 No Replacement Item 9 Quit Program CALL BarMenu Title Item Choice 0 SELECT CASE Choice CASE 1 EXIT DO CASE 2 EXIT DO CASE 3 EXIT DO CASE 4 EXIT DO CASE 5 EXIT DO CASE 6 EXIT DO CASE 7 EXIT DO CASE 8 EXIT DO CASE 9 SCREEN 0 WIDTH 80 25 CLS CLOSE CALL NormalColor PRINT PRINT Program terminated by the user END CASE ELSE REDIM PUText 1 PUText 1 Please Select Sensors 1 through 7 only CALL PopupError END SELECT LOOP IF 8 THEN 0 ELSE RepSens Choice END IF CLS CALL NormalColor END SUB 16 FWOCAL2 BAS March 28 1992 Page 16 690 691 692 FWDCAL2 BAS March 28 1992 17 SUB LatinPage1 SCREEN 0 WIDTH 80 25 CLS Year MID FileDate 1 2 Month MID FileDate 3 2 Day MID FileDate 5 2 MDY Month Day Year PRINT 5 12 SHRP FWD Relative Calibration Latin Square ANOVA Table PRINT FWD SN FWDSN SPC 37 Calibration Date MDY PRINT Data File Name file Ext SPC 32 Data Set SCA of SetCountz PRINT Operator Operator PRIN Ro LERNTE Lat 1 Squa re Des i gn Ana 1 5 1 5 Output kkkkkkkkkkkkkkkkk PRINT Variation S
16. SHRP FWD Relative Calibration Latin Square ANOVA Table SM 8882 861 Calibration Date 95 31 31 Bats File Mame 618053151 RC3 Data Set 1 of Operatar RICK SMITH Variation Sum of Degrees of Pean Computed Critical Source Squares Freedom Sguarg f f nach ARR AO une Position 9 48 02 6 57 82 8 Set 1 35 98 6 26 81 8 Sensor 4 34E 91 6 6 82 2 Error 8 235 88 226 5 7E 82 TOTAL 1 982 93 244 Gain adjustments are indicated and drop set is statistically significant at the 5 level Set significance may be due to warming of the buffers or consolidation of pavement materials during the test A repeat calibration after conditioning the buffers with 58 drops fram height 3 is required to confirm the need for gain adjustments If the deflections from the last 18 drops saru bu more than mil 25 4 microns perform the calibration at a location Fgllp to Gains Table Esc to exit results screens Figure 11 ANOVA table output screen 33 FWDCAL Version 2 Program Manual February 1992 FUD Relative Calibration Gain adjustments FWE SM 5882 851 Calibration Date 85 31 31 Bata File Name 51853151 RC3 Operator RICK SMITH Results of this test indicate the possible need to ad just gains This should be confirmed with a repeat test Gain adjustment should be performed when the new gain factors from two indepe
17. properly For instance for Set 2 mov Sensor 2 to the position formerly occupied by Sensor 1 etc When done in conjunction with reference calibration the relative calibration procedure shall be repeated twice Acceptance criteria based upon the repeatability of the calibration factor are identified in the relative calibration procedure If the results persist in failing the acceptance criteria then the cause of the erratic results should be identified and corrected After the relative calibration is completed the final calibration factors shall be entered into the FWD computer A sample relative calibration setup screen for the Dynatest FWD with version 10 or version 20 software is given in Figure 2 The information in Figure 2 can also be used as the basis for setup of Dynatest FWDs running version 25 and higher software 12 SHRP FWD CALIBRATION PROTOCOL April 1993 Relative Calibration Test UNITS lbf mil inch kPa mu mm Temperature Fahrenheit Centigrade Stn Request OFF ON Test Checks NONE Decreasing defls Roll Off Rol lOFF Decr Reject prompt OFF ON Stationing doesn t matter Temp Request OFF ON Cond Request OFF ON Variation Load NOT Checked Deflections NOT Checked Diameter of Plate 11 8 Deflector distances doesn t matter keep what you have 1 2 3 4 Drop No 1234567 8901234 5678901 2345678 9012345 6789012 34567895 Heights CC44444PCC44444PCC44444PCC44444PCC4
18. supervisor that the results of the tests indicate that the gains need to be adjusted and to provide a check on the determination of the new gain factors to be input into the FWD operating computer program The gains table is the primary determinant of the need to change gains Because it is possible to obtain abnormal results from a single test if a gain change is indicated then it is prudent to verify the results with another test The resulting new relative gain factor from the two tesis should be in close agreement If inconsistent results are obtained then additional tests should be performed after sources for the inconsistencies are investigated Significant or frequent changes in the gain factors may indicate the need for a Reference calibration or the presence of abnormalities in the FWD electronics 18 it FWDCAL Version 2 Program Manual February 1992 ANOVA Table For each source of variation the ANOVA table displays the following information Sum of squares Degrees of freedom Mean Square Computed F Critical F The messages printed on the ANOVA table are conditional on the results of the tolerance checks in the gains table and the significance of the variation sources determined in the ANOVA For each combination of results a separate message is printed as specified in Table 2 for situations when all of the means ratios are within tolerance and Table 3 when a means ratio is outside the tolerance range In th
19. 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 FWDCAL2 BAS March 28 1992 Page 26 WX MOD 5 0 THEN Set Set 1 PRINT 2 END IF NEXT WA PRINT 2 PRINT 2 12 ede de dede de dede dede de ehe dede Summary Stati sti cs Roof dede dede de dede de de dede de jede Page 4 se de de Je de de de e de defe dede dede je dee de e dee e dee dede de de dede dee PRINT 42 SPC 24 Relative Calibration Summary Statistics PRINT 2 FWD SN FWDSN 5 37 Calibration Date MDY PRINT 2 Data File Name file Ext SPC 32 Data Set SCZ of SetCount PRINT 42 Operator Operator PRINT 2 PRINT 42 Load Df1 Df2 0 3 015 0 6 047 Dfi 7 PRINT 35 55 exis sq oux am mue ATTA 1 2 X 2 1 14 La 15 BR HHE HH HRO HE HE ES 6 4 ORL 7
20. Center McLean VA which can be used to determine if the computer and peripherals will work satisfactorily with the program 20 SHRP FWD CALIBRATION PROTOCOL April 1993 APPENDIX B SPECIAL PROCEDURES FOR TESTING THE KUAB FWD Reference calibration of the KUAB FWD can be carried out in a manner very similar to the procedure outlined for the Dynatest FWD However because the KUAB has its load plate forward of the deflection sensor beam 1 toward the towing vehicle it will be necessary to place the trailer on an angle with respect to the test pad so that the load plate can be positioned as close as possible to the LVDT and the deflection sensor holder The end of the aluminum beam holding the LVDT should be just behind the trailer wheels near the place where the foot of the KUAB A frame rests on the floor KUAB FWDs must have operational program SFWD version 4 0 or higher to perform reference calibrations This version can be obtained from the manufacturer Before the reference calibration procedure is performed the FWD Operator should first conduct a static calibration of the deflection sensors The KUAB software will automatically file the static calibration factors The manufacturer recommends that the dynamic calibration factors be entered as 1 05 for all sensors These values should not be changed during or after the reference calibration Due to the larger distance between the center of the load plate and the seismometer h
21. IF DO REDIM Item 4 Title z Item 1 Item 2 Item 3 Item 4 CALL BarMenu Title Item Choice 0 SELECT CASE Choice CASE CASE CASE CASE CASE Select Analysis Type Standard Analysis Replace a Geophone Reference Relative Calibration 3 data sets in file Quit Program 1 Analysis 5 2 Analysis EXIT DO 3 Analysis R EXIT DO 4 SCREEN 0 WIDTH 80 25 CLS CLOSE CALL NormalColor PRINT PRINT Program terminated by the user END ELSE REDIM PUText 1 PUText 1 Please Select an Option CALL PopupError END SELECT LOOP END SUB 31 March 28 1992 31 1297 1298 1299 1300 1301 1302 1303 1504 1305 1306 1507 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 SUB StartAnalysis FOR Sets 1 TO SetCount SCREEN 0 WIDTH 80 25 CLS CALL NormalColor IF Analysis S THEN anat1 Standard relative calibration analysis being performed anat2 on data set STR SetsX in file file Ext anat1 LEN anat1 LOCATE 12 40 anat1 2 PRINT anat1 anat2 LEN anat2 LOCATE 15 40 anat2 2 PRINT anat2 END IF IF Analysis G OR Analysis g
22. SUB StartAnalysis DECLARE SUB OutputToFile DECLARE SUB LatinSqDesign DECLARE SUB SelectAnalysis DECLARE SUB GetSensorNum DECLARE SUB AssignPosition Index Posit DECLARE SUB BadFile DECLARE SUB Quit DECLARE SUB DisplayCopyright DECLARE SUB CheckHeader InitNumPeaks InitNumWHBlocks ExitCode DECLARE SUB ReadPeaks DECLARE SUB ReadNextLine DataType LineLengthX DECLARE SUB GetFileName FPath file Ext SINCLUDE declare inc SINCLUDE cmnblank inc COMMON SHARED cal01 LineCounter amp LineData English Edition ADFlag ADFlag14 FWDSN FileDate NumDef lectors COMMON SHARED cal02 InitNumPeaksX Operator Posit Analysis OExt SumTotal Ti SetCount TOLS RAN COMMON SHARED 03 StdDevDef StdDevPos MeanBySet MeanLoad MeanSet MeanPos MeanDef NumD lt COMMON SHARED cal04 MeanAllLoad StdDevAllLoad CVALtLoad CVPos CVDef MeanAl LDef StdDevAllDef CVAllDef COMMON SHARED cal05 SSLT SSLPos SSLSet SSLSens SSLE FLPos FLSet FLSens COMMON SHARED cal06 DegFreeLPos DegFreeLSet DegFreeLSens DegFreeLEX DegFreeLTA COMMON SHARED cal07 MSLPos MSLSet MSLSens MSLEZ SerialNumX RelGain MeansRat NewGain COMMON SHARED cal08 DefData LoadData OutDef DataSet AvgMeansRat AvgNewGain COMMON SHARED cal09 1 repm2 RepSens BigDef
23. THEN anat1 1 LEN anat1 LOCATE 12 40 1 2 PRINT 1 anat2 LEN anat2 LOCATE 13 40 anat2 2 PRINT anat2 END IF IF Analysis R OR Analysis r THEN FWDCAL2 BAS March 28 1992 Page 32 Replacement geophone relative calibration analysis being performed anat2 data set STR SetsX in file file Ext 1 Relative calibration analysis as part of reference calibration procedure anat2 is being performed on data set STR SetsX in file fileS Ext anat LEN anat1 LOCATE 12 40 1 2 PRINT anat1 anat2 LEN anat2 LOCATE 13 40 anat2 2 PRINT 142 END IF SC Sets K 1 RCount 0 CALL AssignPosition KX Posit FOR MX 1 TO InitNumPeaksX RCount RCount 1 IF NOT English THEN FOR 1 1 TO NumSensorsX Positn 11 4 1 J PositX iX 1 4 K RCount VAL MIDS DataSet Sets PositnA 4 OutDef MX iX VAL MID DataSet SetsX MX Positn 4 NEXT iX LoadData MX VAL MID DataSet SetsX MX 1 4 ELSE FOR 1 1 NumSensors Positn 1 6 33 J 1 lt 1 DefData iX 2 KX RCount VAL MIDS DataSet SetsX Positn 6 OutDef MX iX VALC MIDS DataSet Sets MX PositnA 6 NEXT iX LoadData MX VALC MID DataSet Sets 34 5 END IF IF RCount MOD NumReps 0 THEN RCount 0 K K 1 CAL
24. X CVPos 1 CVPos 2 CVPos 3 CVPos 4 CVPos 5 CVPos 6 CVPos 7 PRINT 2 PRINT 42 CHR 12 END SUB B 26 SUB Quit STATIC CLOSE COLOR 7 0 0 CLS PRINT PRINT file lt gt THEN PRINT PRINT END END SUB FWDCAL2 BAS March 28 1992 Page 27 Output results are contained in file FPath file OExt 27 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 SUB ReadNextLine DataType LineLength STATIC STATIC OldDataTypeX IF NOT EOF 1 THEN LINE INPUT 1 LineData DataType LEFT LineData 1 DataType INSTR SB E 1234567890 DataType OldDataTypeX DataType LineCounter amp LineCounter amp 1 IF DataType 4 THEN IF UCASES LEFTS LineData 3 EOF THEN DataType 1 END IF END IF ELSE DataType 1 of file occurred END IF END SUB 28 FWDCAL2 BAS March 28 1992 Page 28 4 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1250 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 SUB ReadPeaks SetCountX SetCount 1 FOR KX 1 TO InitNumPeaks CALL ReadNextLine DataTypez SELECT CASE DataTypeX CASE 1 EXIT FOR CASE 0 4 EXIT FOR CASE 1 CALL ReadPeaks EXIT SUB CASE 2 EXIT SUB CASE 3 EXIT FOR CASE 5 EXIT FOR CASE ELSE DataSet SetCount END SELECT NEXT KX END SUB LineLength end of file encountered unknown data in Line xxxx
25. be carried out alone at any suitable location There is no corresponding relative calibration procedure for the load measurement system The procedure results in calibration factors which are entered into the FWD software as multipliers When the FWD measurements are multiplied by the calibration factors the result is a measurement which has been corrected to agree with the calibration instrumentation It is necessary that there be a place in the FWD software to enter the calibration factors That is the responsibility of the FWD manufacturer To use this procedure Dynatest FWDs must have Version 10 or higher software Earlier versions do not have the pause feature and do not allow programming the required number of drops in the test sequence Furthermore it is not possible to leave the load plate down as is called for in this procedure Thus Dynatest FWDs must be upgraded to Version 10 or higher software before calibration SHRP FWD CALIBRATION PROTOCOL April 1993 FREQUENCY OF CALIBRATION Reference calibration should be performed at least once per year or as soon as possible after a sensor has been replaced on the FWD Relative calibration should be performed on the deflection sensors at least once per month It should also be performed immediately after a deflection sensor 1s replaced PERSONNEL FWD System Operator Calibration System Operator REFERENCE CALIBRATION PROCEDURE Equipment Preparation The FWD should be in good
26. be developed 23 SHRP FWD CALIBRATION PROTOCOL April 1993 APPENDIX C 4MPLE COMPUTATION OF FINAL CALIBRATION FACTORS Final Calibration Factors From Relative Calibration Average Final Standard Sensor Trial 1 Trial 2 Trial3 Calibration Factors Deviation 1 1 014 1 011 1 015 1 013 0 0035 2 1 010 1 007 1 012 1 010 0 0035 3 1 012 1 010 1 013 1 011 0 0035 4 1 016 1 020 1 012 1 016 0 0035 5 1 017 1 018 1 018 1 018 0 0035 6 1 008 1 012 1 011 1 010 0 0035 7 1 012 1 012 1 009 1 011 0 0035 Notes 1 If the results from the first two trials agree within 0 003 for each deflection sensor then it is not necessary to perform a third test Average the results of the first two trials and enter the ave age final calibration factors in FWD computer In the example above after Trial 2 the data marked 7 did not meet this criterion 2 If three trials are performed compute the mean and the standard deviation of the three results for each deflection sensor If the standard deviations based on n 1 degrees of freedom are all less than 0 003 enter the average final calibration factors in the FWD computer If any of the standard deviations exceed 0 003 repeat the entire relative calibration test 24 SHRP FWD CALIBRATION PROTOCOL April 1993 APPENDIX D REFERENCE LOAD CELL CALIBRATION PROCEDURE INTRODUCTION The reference load cell is a precision instrument capable of measuring loads within 0 3 percent or better Such a
27. does not provide the high degree of accuracy that is required for this calibration Bearing blocks special wood aluminum bearing blocks Measurements Group Inc Model 2310 Signal Conditioner This should be the same signal conditioner that will be used in the reference calibration procedure 25 SHRP FWD CALIBRATION PROTOCOL April 1993 e Keithley MetraByte DAS 16G data acquisition board installed in the same computer that is used for reference calibration e Push button trigger for activating the data acquisition system The reference load cell and its cable and the associated signal conditioner data acquisition board and computer should be considered a system of instruments which should be calibrated together and used together CALIBRATION OF EQUIPMENT The universal testing machine should be calibrated according to ASTM procedure E 74 within twelve months prior to conducting this procedure The device s used to calibrate the universal testing machine should be certified to be traceable to the National Institute for Science and Technology NIST formerly the National Bureau of Standards calibration s The certificate of calibration provided for the universal testing machine should be used to develop an adjustment algorithm which will correct the indicated load on the universal testing machine to the NIST load It is highly recommended that the reference load cell be calibrated soon after the universal testing machine
28. is calibrated The MetraByte board should be calibrated according to the procedure described in the manufacturer s instruction manual Its accuracy should be verified using a reference voltage source such as a 1 350 volt mercury cell eg camera battery in new condition The 2310 signal conditioner amplifier should be balanced according to the procedure described in the manufacturer s instruction manual With the signal input terminals shorted together at gain 100 the ac noise on the 10 volt output terminals should be 1 millivolt or less EQUIPMENT PREPARATION Inspect the reference load cell carefully before calibration Verify that the cable and the Amphenol connectors are making proper contact in their sockets eg fitting and locking tightly Make a continuity check to verify that there are no breaks in the wires Verify that the Allen screws on the load cell are tight Note The six Allen screws on the top and the bottom of the load cell were torqued to 100 lb in and set with Locktite during assembly These screws should not be loosened unless it is absolutely necessary If any of the screws are loosened they should be removed one at a 26 SHRP FWD CALIBRATION PROTOCOL April 1993 time and their threads cleaned Locktite should be reapplied to their threads and they should be torqued to precisely 100 Verify that the three steel pads on the bottom of the reference load cell are in good condition Verify that one
29. make this easier a double layer or thicker of duct tape should be wrapped around the guide post down which the runners under the falling mass roll located an inch or two above the bottom of the stroke The proper position for the tape can be found when the mass is at its lowest drop height Adjust the KUAB load sensitivity in the reference system computer to a value of 5 to 10 bits Remove the tape after completion of the reference calibration Enter the new calibration factors for the deflection sensors as the SHRP Calibration Factors under the Calibrate menu in the KUAB operational program The calibration factor for the 300 mm load plate is entered in the same manner The calibration factor for the large 450 mm load plate should remain unchanged Most KUAB FWDs do not have a calibration stand for performing relative calibration Thus it will not be possible to perform the relative calibration procedure as described herein 22 SHRP FWD CALIBRATION PROTOCOL April 1993 Limited experience in the calibration of KUAB FWDs has shown that the combination of static calibration and dynamic calibration may be adequate to yield a satisfactory calibration and accurate final calibration factors However relative calibration further refines the reference calibration factors and it allows a monthly check of the accuracy of the deflection sensors Thus it is highly recommended that a means of performing relative calibration with the KUAB FWD
30. of the brace between the two columns that surround the cylinders that raise and lower the load plate If the clearance is too small reposition the target for the fourth drop height to achieve the required clearance This SHRP FWD CALIBRATION PROTOCOL April 1993 should assure that there will be adequate clearance when the reference load cell is in position under the load plate Before beginning any calibration work and throughout the entire calibration period it is necessary that there be no data filters in operation in the FWD Verify that the peak smoothing processor has been turned off This feature is accessed from the Dynatest Main Menu by selecting Road Options item 3 followed by item 12 where Peak Readings should show direct and not smooth General Procedure The FWD load cell should be calibrated at least twice Multiple calibration tests are performed on the load cell and the results are averaged since it is not possible to perform relative calibration on the load cell Acceptance criteria based upon the repeatability of the calibration factor are identified in the load cell calibration procedure If the results persist in failing the acceptance criteria then the cause of the erratic results should be identified and corrected Each deflection sensor shall be calibrated once Spare deflection sensors do not have to be calibrated until they are in active use After all load and deflection sensors have been calibr
31. of the wood aluminum bearing blocks has a ribbed rubber pad cemented to it If the edges of the rubber pad are loose use rubber cement to reattach it Install a spherically seated bearing block in the cross head of the universal testing machine Make the following settings on the front panel of the 2310 signal conditioner Excitation Voltage set to 10 volts e Filter set to 1000 Hz AC IN button fully extended eg Gain set to 5 5 x100 Auto Balance switch OFF Verify that the Tape Playback switch on the rear panel of the signal conditioner is OFF Position the signal conditioner and the computer several feet apart near the testing machine and attach them to ac line power COMPUTER PREPARATION Use the same computer system for reference load cell calibration that is used for FWD calibration A graphics printer must be available Load the software LDCELCAL into the reference system computer This program should be located in the same subdirectory with FWDREFCL EXE and FWDREFCL CNF A disk with the files REFLCCAL WK1 and REFLCCAL FMT on it should be inserted in drive A The computer must be running under DOS and not under WINDOWS during the calibration The computer program LDCELCAL is designed to interact with a Lotus 1 2 3 version 2 3 spreadsheet to accomplish the data analysis The subdirectory containing the 1 2 3 program must be on the PATH in order for the two programs to work together successfully The WYSIWYG add
32. plate is near the center of the calibration test pad or on any other stiff smooth surface Verify that there is no sand or other loose debris SHRP FWD CALIBRATION PROTOCOL April 1993 Table 1 FWD Calibration Data Reporting Requirements Data Item FWD Operator Name Calibration System Operator Name Date and Time of Calibration FWD Serial ID Number FWD Manufacturer FWD Owner FWD Load Cell Serial Number FWD Deflection Sensor Serial Numbers Reference Load Cel Serial Number Reference LVDT Serial Number FWD Calibration Center Location Current Calibration Factor for FWD Load Cell Current Cal Factors for FWD Deflection Sensors Ref Load Cell Calibration Constants Ref Load Cell Calibration Date Ref LVDT Calibration Constants Ref LVDT Calibration Date FWD Load Cell Readings 20 total Ref Load Cell Readings 20 total FWD Deflection Readings 20 per sensor Ref LVDT Readings 20 per sensor Interim Cal Factors from Reference Calibration FWD Relative Calibration Data Calibration Factors from Relative Calibration Final Calibration Factors Mode of Ent Manual Manual Automatic Manual Manual Manual Manual Manual Automatic Automatic Automatic Manual Manual Automatic Automatic Computed Automatic Manual Automatic Manual Automatic Computed Automatic Computed Manual Source Operator Operator Computer Clock Operator Operator Operator Transducer Setup and Gain Printout Tran
33. relative gain factor for a series of three tests and the average gain factor from the tests three data blocks for the tests must be contained in the same file The standard analysis and replace geophone analysis can be run on data files containing 1 2 or 3 data blocks in the same file After the analysis type is selected the program reads the data file If multiple relative calibration data blocks are found the program displays a message indicating how many data blocks were found For data files containing multiple data blocks the program simply cycles through the program and treats each data block separately The results are written to the same output file 27 FWDCAL Version 2 Program Manual February 1992 tal v VM A AP SES Sasa n A m p 0 A an 922 S Vivere EAE SSS x DUANE NARI UE ARAS tts A fene p Pa v eheu tg wee 1 Standard Analysis 2 Replace a Geophone 3 Reference Relativge Calibration 3 data sets in file 3 Quit Program 14 Home End Figure 6 Select analysis control screen ORA lo d 44 Vie ura M Directory path for data file H NLANGUAGENBASICNQBNCHNRAJS bo you want list
34. serial number Deflection sensor gain settings Operators names The FWD data block consists of a repeating series of lines defining the test sequence of five repeat drops for each position arrangement The first line in the data block identifies the location station of the test the character S always occupies the first column in this line The lines following are the data recorded for each drop If English units are used the load and deflection data are written twice on the same line once in metric and then in English units If metric units are used only the metric measurements are present An excerpt from a Dynatest FWD relative calibration data block in English units is shown in Figure 1 FWDCAL Version 2 Program Manual February 1992 File Contents Column 11111111112222222222333333333344444444445555555555566666666677777777778 12345678901234567890123456789012345678901234567890123456789012345678901234567890 5 28 27 23 161626 80 73 Heights 1596 441 443 442 443 443 442 441 25360 17 37 17 44 17 40 17 43 17 42 17 42 17 38 1580 452 452 452 452 451 452 452 25104 17 78 17 78 17 78 17 79 17 77 17 80 17 79 1593 459 460 460 460 460 460 459 25312 18 07 18 12 18 11 18 12 18 12 18 10 18 07 467 466 466 467 466 465 25208 18 31 18 37 18 35 18 36 18 38 18 36 18 32 gt Ld e e gt
35. test should be repeated after the testing site has been further conditioned according to the procedure If the deflection readings do not become relatively constant during the conditioning then another site should be selected for the testing The mere fact that either position or set or both are significant does not necessarily invalidate the relative calibration Judgement must be used to assess whether or not these factors may be of sufficient physical significance as opposed to statistical significance to require that the relative calibration should be repeated or that a new test site should be selected The standard error of measurement e g the square root of the mean square error due to error should be on the order of 0 08 mils 2 microns or less if the system is working properly and the calibration test was conducted carefully The analysis of the data obtained from the relative calibration procedure and the method used to determine revised calibration factors is as follows calculations are done automatically within the FWDCAL2 software 1 Compute the mean deflection measurement for each sensor average for the seven sets and the overall mean x for all of the sensors averaged together 2 Compute the adjustment ratio R of the overall mean to the sensor mean for each Sensor 15 SHRP FWD CALIBRATION PROTOCOL April 1993 Adjustment of Calibration Factors When relative calibration is conducted in co
36. the File Selection Screen e FWDCAL Version 2 Program Manual February 1992 Anomalous Results Depending on the results of the calibration analysis procedure a number of scenarios exist for the case of apparently bad or anomalous data For all scenarios the first two remedial steps should consist of reviewing the echo print of the input data to identify any irregular or unusual conditions If a problem exists in the header block or data format another possibility might be to review the contents of the input file using a text editor and correct any format inconsistencies and then repeat the analysis As suggested in the user messages contained in the ANOVA table several possible sources of abnormal results from the relative calibration test include Failure to keep the stand vertical with moderate downward pressure applied This typically results in position being statistically significant Systematic change in the applied load to the pavement Typically the load will decrease during the conduct of the test This can be due to a change in the resiliency of the buffers or a change in the pavement structure Remedial actions include further conditioning of the buffers with additional drops or movement to a new location This condition can be detected by inspection of the change in the load level between drop sets and the occurrence of set being statistically significant Failure to place the stand in the exact same poi
37. the micrometer and X is the corresponding voltage output in bits as read by the computer data acquisition board The FWDREFCL software provides prompts for this entire process reads and records the requisite data and performs the computations The slope m will be approximately 1 00 microns per bit The standard error of the slope should be less than 0 0010 If a larger standard error is obtained the LVDT calibration should be repeated Enter the LVDT calibration results into the computer data acquisition system This is handled automatically by the FWDREFCL software After the calibration results are entered the signal conditioner gain must not be changed Secure the LVDT in its holder on the reference system aluminum beam so that it 1s near the null point eg zero voltage output Verify with a spirit level that the LVDT 15 vertical in its holder If it is not vertical adjust the position of the aluminum beam to a ain verticality This may require shimming the beam where it is bolted to the concrete block Position the FWD trailer so that the load plate is as close as possible to the deflection sensor holder It is important however that the FWD should not come in contact with the beam or any other part of the reference system during the testing Remove the deflection sensors from their holders on the FWD beam and verify that they are free of dirt and grime which would adversely affect their seating in the reference s
38. the other geophones This can occur even though the mean response is the same as the other sensors Cochran s test for the homogeneity of variances is used The Cochran statistic is Largest 52 8 NumSens 5 2 8 where NumSets NumReps NumSetsxNumReps M 2 k 1 1 1 NumSets x NumReps NumSets x NumReps 1 6 52 sample variance for deflection response of sensor i for all drops NumSets NumReps Number of drop sets Number of repeat drops in each drop set 11 FWDCAL Version 2 Program Manual February 1992 To determine significance the computed value is compared against the critical g If g gt g then the hypothesis of equal variances is rejected For 7 sensors and 35 measurements 2505 0 2326 This procedure provides test on the homogeneity of the sensor variance and also provides an indication of which sensor has the greatest variance The results of this test are only printed if the computed 2 value is in the critical region Program Output The program output is organized into the following screens pages Gains Table ANOVA Table Deflection Input Data Summary Statistics An example of the four page output file from the program is shown in Figures 2 5 The output file created by the program has a name that consists of the original data file name with an extension of the form Cx7 where x indicates the type of analysis S for standard analysis G for re
39. to jump to the first or last entry in the menu respectively An example of this screen is shown in Figure 8 Control Screen 4 Display Results on Screen Field 1 Output file name the name of the output file is shown The output file name consists of the original file name with the extension where x indicates the type of analysis S for standard analysis G for replace geophone analysis and R for Reference relative calibration 5 the last character in the data file name extension for example it would be the 1 in the file name 59092289 RC1 Field 2 If a Y is entered the Output Screens 1 and 2 are displayed to show the Gains Table and the ANOVA Table on the screen The program writes the output files to the same directory as the FWD data files indicated in Control Screen 1 The output file naming convention was created so that the output files from multiple relative calibration tests performed on the same day using the SHRP relative calibration file naming convention would not over write each other The input file should always contain a unique character in the right most digit of the file name extension An example of this control screen is shown in Figure 9 30 FWDCAL Version 2 Program Manual February 1992 2 SE a v AS CMM gt errs oe vv deve nte e S id H1 gt Sensor No 848 Sensor No 9836 Sensor No 833 Sensor No 834 S
40. to be statistically significant at the 5 level If the computed F value is greater than the critical F statistic then the corresponding H hypothesis is rejected and the effect is indicated as being statistically significant C 4 Long Term Pavement Performance Advisory Committee Chairman William J MacCreery W J MacCreery Inc David Albright Alliance for Transportation Research Richard Barksdale Georgia Institute of Technology James L Brown Pavement Consultant Robert L Clevenger Colorado Department of Highways Ronald Collins Georgia Department of Transportation Guy Dore Ministere des Transports de Quebec Charles E Dougan Connecticut Department of Transportation McRaney Fulmer South Carolina Department of Highways and Public Transportation Marlin J Knutson American Concrete Pavement Association Hans Jorgen Ertman Larsen Danish Road Institute Road Directorate Kenneth H McGhee Consultant Civil Engineer Raymond K Moore University of Kansas Richard D Morgan National Asphalt Pavement Association William R Moyer Pennsylvania Department of Transportation David E Newcomb University of Minnesota Charles A Pryor National Stone Association Cesar A V Queiroz The World Bank Roland L Rizenbergs Kentucky Transportation Cabinet Gary K Robinson Arizona Department of Transportation Frederic R Ross Wisconsin Department of Transportation Ted M Scott American Trucking Association
41. 10 drops vary by more than 1 mil 25 4 microns PRINT 2 repeat the calibration at new location If this message appears the PRINT 42 subsequent tests contact the supervising engineer for further instructions CASE NNN PRINT 2 Results indicate that no gain adjustments are needed CASE NYN PRINT 2 Sensor is statistically significant at the 5 level but gain do not needed PRINT 42 to be adjusted Test results should be reviewed carefully If anything is PRINT 2 suspect repeat the calibration Otherwise these results are acceptable CASE NNY PRINT Z2 Gains do not needed to be adjusted but stand position is statistically PRINT 42 significant at the 5X level This may be caused by failure to keep the stand PRINT 2 vertical or improper seating of the geophones In the future care should be PRINT 2 taken to ensure that the geophone bases are clean and well seated and the PRINT 42 stand is kept vertical with a moderate downward pressure CASE NYY PRINT 2 Sensor and stand position are statistically significant at the 5 level but PRINT 42 gain adjustments are not indicated Review calibration results carefully PRINT 2 If anything is suspect repeat the calibration taking care to ensure that PRINT 42 geophone bases are clean and properly seated and the stand is kept vertical PRINT 2 with moderate downward force applied CASE ELSE END SELECT END IF B Y
42. 26 18 17 18 17 18 12 18 30 18 19 5 1 22 072 18 12 18 22 18 09 18 17 18 08 18 22 18 19 5 2 22 000 18 29 18 34 18 30 18 33 18 25 18 35 18 36 5 3 21 984 18 16 18 30 18 17 18 25 18 16 18 26 18 28 5 4 22 048 18 12 18 22 18 17 18 21 18 12 18 26 18 23 5 5 22 000 18 33 18 43 18 30 18 42 18 29 18 44 18 41 6 1 22 040 18 12 18 22 18 05 18 04 18 16 18 17 18 15 6 2 22 080 18 20 18 22 18 09 18 12 18 12 18 22 18 19 6 3 21 984 18 29 18 30 18 22 18 17 18 25 18 30 18 32 6 4 21 952 18 41 18 43 18 34 18 33 18 37 18 44 18 41 6 5 21 928 18 07 18 09 18 01 17 96 18 04 18 13 18 06 7 1 22 008 18 12 18 22 18 13 18 04 18 25 18 22 18 19 7 2 22 008 18 03 18 13 18 01 17 96 18 12 18 17 18 15 7 3 21 920 18 33 18 38 18 30 18 25 18 37 18 39 18 36 7 4 22 032 18 29 18 43 18 26 18 21 18 42 18 39 18 41 7 5 21 952 18 20 18 30 18 17 18 12 18 29 18 30 18 28 Figure 4 Example print of output file of input listing FWDCAL Version 2 Program Manual February 1992 Relative Calibration Summary Statistics FWD SN 8002 061 Calibration Date 05 31 91 Data File Name 61053191 RC3 Data Set 1 of 1 Operator RICK SMITH Load Df1 Df2 Df3 2 4 Df5 Df6 Df7 Df1 7 Set 1 Avg 22 061 18 16 18 20 18 12 18 04 18 11 18 14 18 16 18 13 Set 2 Avg 22 053 18 23 18 29 18 23 18 13 18 13 18 22 18 23 18 21 Set 3 22 074 18 18 18 38 18 24 18 22 18 20 18 27 18 28 18 25 Set 4 Avg 22 043 18 40 18 51 18 42 18 43 18 39 18 51 18 45 18 44 Set 5 Avg 22 021 18 20 18 30 18 21 18 28 18 18 18 31 18 29 18 25 Set
43. 3333344444444445555555555566666666677777777778 12345678901234567890123456789012345678901234567890123456789012345678901234567890 R80 73 8906065806068936F 10 700031018002 05875568 6303111 6 1500 203 305 457 610 914 1524 5 9 0 C NFWDNDATAN FWD S 28 27 23 38 80 73 Heights rere 5 28 27 23 80 75 Heights 808 207227303730 005 005 18 15 355 2 1 2 8 Ld 110 1 014 92 01 801 987 1 059 02 802 986 1 093 03 803 985 1 066 04 804 983 1 045 05 805 985 1 126 06 806 981 1 108 07 807 1 059 00 808 1 079 00 809 00 810 11020600 16388 4839 123P45678P90123P45678P90123P45678P90123P45678S 44444 24444 44444 44444 44444 44444 44444 1111111111111111114444444444242444 FWDCAL Version 2 Program Manual February 1992 The program is terminated if any of the following conditions are found during the checks performed on the header block The Dynatest FWD operating software is not either edition 10 or 20 If the number of sensors is not equal to 7 If there less than 46 total active drops indicated line 30 The number of active drops is determined by the column number of the first period found on line 30 If there are not 5 repeat drops for each drop set Other information determined from the header block and used by the program include Units for data collection English Metric Data collection date FWD
44. 4444PCC44444PC0444448 1111111 Test Plots Save Peaks x 2 2 Load His Whole His Load another TEST SETUP 19 Store the CURRENT TEST SETUP Note Drop height should be adjusted to attain deflections within the specified range Figure 2 Relative Calibration Test Setup for the Dynatest FWD Relative Calibration of the Deflection Sensors 1 Remove all of the deflection sensors from their holders on the FWD sure that the sensors are labeled e g from 1 to 7 or to 6 with respect to their normal position on the FWD center sensor is in position number 1 on the Dynatest FWD and in position number 0 on the KUAB FWD Label the seven levels on the sensor stand from A to The top level is usually labeled A Position the seven deflection sensors in the stand for the first of the seven sets Support the sensor stand in a vertical position Mark the location where the stand rests so that it can be relocated precisely on the same spot This may be done by gluing a washer to the pavement or by making a small divot in the pavement with a chisel Select the FWD drop height and the distance from the loading plate to the sensor stand to yield deflections on the order of 400 to 600 microns 16 to 24 mils If deflections in 13 SHRP FWD CALIBRATION PROTOCOL April 1993 this range cannot be achieved then it may be necessary to re
45. 6 Avg 21 997 18 22 18 25 18 14 18 12 18 19 18 25 18 23 18 20 Set 7 Avg 21 984 18 19 18 29 18 17 18 12 18 29 18 29 18 28 18 23 Averago 22 033 18 23 18 32 18 22 18 19 18 21 18 28 18 27 18 25 Std Dev 54 0 19 0 21 0 20 0 23 0 21 0 21 0 20 0 210 0 25 1 06 1 13 1 12 1 27 1 16 1 15 1 09 1 15 1 2 3 4 5 6 7 Avg Df 18 26 18 25 18 25 18 22 18 22 18 24 18 28 Std Dev 0 20 0 20 0 22 0 23 0 21 0 22 0 20 COV 1 09 1 09 1 22 1 24 1 16 1 20 1 12 Figure 5 Example print of output file of summary statistics 16 FWDCAL Version 2 Program Manual February 1992 Gains Table The gains table displays the following information Existing gain settings read the input data block The computed means ratio for each sensor The new relative gain factor based on the test results Indicates if the means ratio for sensor is side the range of 1 000 0 003 Indicates if the new relative gain factor is outside the 2 range of 0 980 1 020 The following messages are printed If of the means ratios is side of the tolerance limit Warning At least one sensor is outside of the tolerance limit Verify these results with an additional test RESULTS INDICATE THAT THE SENSOR GAINS SHOULD BE RESET If one of the means ratios is outside the tolerance range then the following message is shown on a separate screen displayed after the ANOVA output screen and is printed on the gains table in the output file
46. AL Version 2 Program Manual February 1992 This is the sensor serial number read from the header block Each sensor has an serial number assigned by the manufacturer This number is used by the FWD operating program to determine the proper processing parameters for each sensor This is the current gain setting read from the header block This is the computed ratio of the average response of all sensors to the response of each individual sensor tolerance range is set for this number to indicate the need for adjustment of the gain factor This is the new relative gain factor computed from the results of the test This is the number that would be entered into the FWD operating program if the gain factors need to be changed The overall mean deflection response is computed as follows where x NumSens NumSets Numkeps NumSens NumSets NumReps 1 2 ie Li NumSens x NumSets x NumReps average deflection for all sensors Number of sensors 7 for SHRP FWD Number of drop sets 7 for SHRP relative calibration test This should be equal to the number of sensors and number of positions in the stand Number of repeat drops for each drop set 5 for SHRP relative calibration test deflection for sensor i drop set k and repeat drop a FWDCAL Version 2 Program Manual February 1992 The mean deflection response for each sensor is computed as E tel 11 NumSets x NumReps where X
47. CALL Normal Color FOR 1 1 TO NumSensors AvgNewGain i NewGain 1 iX NewGain 2 1 NewGain 3 1 3 NEXT iX 1 4 Pede de de je de de de de e de de de defe de ede de dede de jede de dede dede Year MiD FileDate 1 2 Month MID FileDate 3 2 Day MDY MID FileDate 5 2 Month Day Years V see Ve dee dede dede Geophone Calibration Sensor kik k dede fe dede vede dede dede dede PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT t8 SPC 14 SHRP FWD Relative Calibration Average Gains Table FWD SN FMDSN SPC 38 Calibration Date MDYS Data File Name file Ext 5 12 Average Means and Gains for 3 data Sets Operator Operator Sensor Existing New Relative Gain Sensor S N Gain Factor Set 1 Set 2 Set 3 Average 5 HHH HHE ORL HHA FOR S 1 TO NumSensorsX PRINT USING t8 SX SerialNumX SX RelGain S NewGain 1 SX NewGain 2 5 NewGain 3 5 AvgNewGainz SX NEXT SX LOCATE 25 25 PRINT Press any key to continue WHILE INKEYS WEND END SUB FWDCAL2 BAS March 28 1992 Page 6 SUB BadFile STATIC CLOSE COLOR 7 0 0 CLS PRINT PRINT PRINT EXECUTION HALTED PRINT The data file selected does not match the structure specified PRINT for relative calibration in FWD Operational Field Guidelin
48. Compute Std Dev for the data set dee kkk Jedededesesesehededek FOR 1 1 TO NumSensors FOR KX 1 TO NumSetsz MeanBySet iX Tiks iX NumReps NEXT KX MeanDef i 1 NumSensors NumReps4 MeanPos i 1 NumPositionsX NumRepsA MeanSet i 1 NumSets NumRepsA NEXT iX SSumLoad 0 TotalAllLoad 0 Set 1 FOR DX 1 TO NumSetsX NumReps SSumLoad SSumLoad LoadData D 2 20 FWOCAL2 BAS March 28 1992 21 837 TotalALlLoadZ TotalAllLoad LoadData DX 838 TotalLoad SetX TotalLoad Set LoadData DX 839 IF DX MOD 5 0 THEN Set Set 1 MeanLoad SetX 1 TotalLoad Set 1 5 840 NEXT DX 841 MeanAllLoad TotalAllLoad NumSets NumReps 842 StdDevAllLoad SQR SSumLoad NumSetsX NumRepsX MeanAllLoad 2 NumSetsX 843 1 844 CVAllLoad StdDevAllLoad MeanAllLoad 100 845 MeanALlDef SumTotal NumSensors NumSets NumReps 846 StdDevAllDef SQR TotalSS NumPositions NumSetsX NumReps SumTotal NumPositionsA 847 NumSets NumReps 2 NumPositions NumSets NumReps 10 848 CVAllDef StdDevAllDef MeanAllDef 100 849 FOR 1 1 TO NumSensorsX 850 StdDevDef iX SQR SSumTi i NumSensorsX NumReps 11 1 NumSensors NumReps 2 851 NumSensorsX NumReps 10 852 StdDevPos iX SQR
49. D FLPos CritFLPos lt 0 AND FLSet CritFLset lt 0 THEN LSAMS END IF IF Jnum1X gt 0 THEN SELECT CASE LSAM CASE YNN PRINT 42 Gain adjustments are indicated and drop set is statistically significant at PRINT Z2 the 5X level Set significance may be due to warming of the buffers or i PRINT 2 consolidation of pavement materials during the test A repeat calibration PRINT 2 after conditioning the FWD buffers with 50 drops from height 3 is required PRINT 42 to confirm the need for gain adjustments If the deflections from the last 10 PRINT 2 drops vary by more than 1 mil 25 4 microns repeat the calibration ata PRINT 2 new location 1065 1066 1067 1068 1069 1070 1071 1072 1073 FWDCAL2 BAS March 28 1992 24 CASE YYN PRINT 2 Gain adjustments are indicated and sensor and drop set are statistically n PRINT 2 significant at the 5 level A repeat calibration after conditioning the FWD PRINT 2 buffers with 50 drops at height 3 is required to confirm the need for gain PRINT 2 adjustments If deflections for the last 10 drops vary by more than 1 mil PRINT 42 25 4 microns repeat the calibration at a new location CASE YNY PRINT 42 Gain adjustments are indicated and set and stand position are statistically PRINT 42 significant at the 5X Level A repeat calibration after conditioning the FWD PRINT 42 buffers with 50 drops at height 3 i
50. G ProblemExist SC Jnum1 Jnum2 LSAMS The determination of significance is based hard coded F Statistic or a given set of degrees of freedom and confidence level To modify the determination of significance the user must change the value for FStatistic in this code CONST TrueX 1 False 0 CritFLPos 2 14 CritFLset 2 14 CritFLSens 2 14 CONST NumSensorsX 7 NumPositions 7 NumSets 7 NumRepsA 5 Galph 2326 DIM DefData 7 7 7 5 LoadData 35 OutDef 35 7 DataSet 3 35 DIM Posit 7 MeanSet 7 MeanPos 7 MeanDef 7 MeanLoad 7 DIM CVPos 7 CVDef 7 StdDevDef 7 StdDevPos 7 MeanBySet 7 7 DIM Ti 7 RelGain 10 NewGain 3 10 MeansRat 3 7 Serial NumX 10 DIM AvgNewGain 7 AvgMeansRat 7 01 7 RANS 7 GP Monitor Monitor CALL DisplayCopyright FPath Start SCREEN 0 WIDTH 80 25 CLS RepSensX 0 NumStations 0 SetCount 0 CLOSE CALL SelectAnalysis CALL GetFileName FPath file Ext Source FPath file Ext OPEN Source FOR INPUT AS 1 CLS CALL NormalColor LOCATE 13 20 PRINT Reading Input Data from file Ext LineCounter amp 0 DO FWDCAL2 BAS March 28 1992 Page 2 IF LineCounter amp lt 37 THEN CALL CheckHeader InitNumPeaksX InitNumWHBlocks ExitCede ELSE CALL ReadNextLine DataTypeX LineLength SELECT CASE DataType CASE 1 CALL ReadPeaks deflection data bloc
51. L AssignPosition K PositA END IF NEXT CALL LatinSqDesign IF Analysis 6 AND RepSens gt 0 THEN CALL ReplaceSensor END IF CALL OutputToFile IF Analysis R THEN CALL FileToScreen END IF NEXT Sets END SUB B 32 FWDCAL Version 2 Program Manual February 1992 Appendix C Latin Square Analysis of Variance ANOVA FWDCAL Version 2 Program Manual February 1992 Latin Square ANOVA The Latin Square experiment design layout for the relative calibration test is shown in Table 1 In this design the sensor number S represents the treatment for each combination of drop set and stand position Drop set represents the 5 drop sequence used to test each combination of sensor and stand position For purposes of classification within each cell in the experiment design the measured deflections are designated as where i represents the sensor number j represents the position in the stand represents the drop set and represents the repeat drops in each drop set An equivalent and more convenient designation for the deflection values is where the subscripts are the same as above This is because position in the stand is dependent on sensor number and drop set All combinations of i k and do not exist in the data set Table 1 7x7 Latin square design for relative calibration analysis Position Drop Set FWDCAL Version 2 Program Manual February 1992 The response model for th
52. P 6 4P 6 The pause occurs with the mass elevated ready to drop The mass will not be released until the FWD operator strikes a key To repeat the drop sequence without raising the load plate from the ground strike the ESC key twice immediately following the final drop This will interrupt the initial drop sequence allowing a second drop sequence to be started without raising the plate Because the top of the reference load cell is 300 millimeters in diameter it will only be possible to calibrate the small 300 mm load plate on the KUAB If the KUAB is outfitted with the large 450 mm load plate it should be replaced with the 300 millimeter load plate in order to attain accurate results A special holder is provided for mounting the KUAB seismometer under the LVDT The Dynatest geophone holder should be removed and the KUAB holder bolted down in its place The LVDT mounting plate that ati ches to the end of the aluminum beam should be removed from its position under the beam and reinstalled on top of the beam The KUAB deflection sensors will be slid upward off the two rods that hold them in position on the sensor beam in the trailer Remove the tripod foot by loosening its holding screw and then slip the deflection sensor over the peg on the holder under the LVDT Tighten the holding screw firmly Conducting load plate calibration is particularly difficult on the KUAB because it is hard to detect when the FWD mass has been released To
53. Reference Relative Calibration is designed to be used for the relative calibration performed in conjusztion with the SHRP Reference calibration procedure This analysis option computes the average new gain setting for a series of three tests The program is written in Microsoft QuickBasic 4 5 It uses a proprietary file selection routine written by PCS LAW Engineering It also utilizes commercial routines written by Crescent Software for the menu s and windows A listing of the FWDCAL Version 2 program is presented in Appendix B The routines from Crescent Software are not included in the listing All of the analyses follow the same basis steps which consist of FWD data file input gains table latin square ANOVA summary statistics and program output These topics are described in the following sections FWD Data File Input Each Dynatest FWD data file consists of header information and data block s The first 37 lines of the Dynatest data file contains the header information An example is shown in Table 1 The second part of the data file known as the data block consists of the loads deflections temperatures and station information A data file can contain multiple data block sets referred to as data sets in a file that contains only one header block e OONnN OU FWDCAL Version 2 Program Manual February 1992 Table 1 Example of Dynatest FWD header block File Contents Column 1111111111222222222233333
54. SHRP FWD Relative Calibration Gain Adjustment Results of this test indicate the possible need to adjust the gains This should be confirmed with a repeat test Gain adjustment should be performed when the New Gain Factors for two independent calibrations are within 0 002 of each other Gain adjustments should be made ONLY to the out of range geophone s After adjusting any gain setting the relative calibration test must be repeated to confirm that all sensors are within tolerance 17 FWDCAL Version 2 Program Manual February 1992 If one of the New Relative Gain factors are outside the 2 range Warning At least one sensor is outside the 2 range limit Notify Supervising Engineer after verifying with additional tests e If the replace sensor analysis is selected and if the means ratio is outside the tolerance range then for the replaced sensor Means Ratio for Sensor No is outside the tolerance range example message above If the replace sensor analysis is selected and if the means ratio is inside the tolerance range then for the replaced sensor indicated as in the example message below Means Ratio for Sensor No is within the tolerance range An example gains table output is displayed in Figure 2 In these messages the user who is assumed to the FWD operator is advised to contact the supervising engineer prior to making any gain changes This serves to notify the responsible
55. SHRP P 652 Falling Weight Deflectometer Relative Calibration Analysis PCS Law Engineering Strategic Highway Research Program National Research Council Washington DC 1993 SHRP P 652 Contract P 001 Program Manager Neil F Hawks Project Manager Cheryl Allen Richter Production Editor Marsha Barrett Program Area Secretary Cynthia Baker August 1993 key words calibration deflection testing and backcalculation falling weight deflectometer FWD LTPP AC Strategic Highway Research Program National Academy of Sciences 2101 Constitution Avenue N W Washington DC 20418 202 334 3774 The publication of this report does not necessarily indicate approval or endorsement of the findings opinions conclusions or recommendations either inferred or specifically expressed herein by the National Academy of Sciences the United States Government or the American Association of State Highway and Transportation Officials or its member states 9 1993 National Academy of Sciences 350 NAP 893 a Acknowledgments The research described herein was supported by the Strategic Highway Research Program SHRP SHRP is a unit of the National Research Council that was authorized by section 128 of the Surface Transportation and Uniform Relocation Assistance Act of 1987 The development of this program was sponsored by the Strategic Highway Research Program for use in the Long Term Pavement Performance LTPP Studies Techn
56. SSumTj4 iX NumPositionsX NumReps 1 2 NumPositions 853 NumReps 1 854 CVDef iX StdDevDef iX MeanDefZ iX 100 855 CVPos iX StdDevPos iX MeanPos i 100 856 MeansRat SC 1 MeanAllDef 1 857 NewGain SC 1 MeansRatZ SCX 1 RelGainZ iX 858 NEXT iX 859 8 e dee e dede e he dee e e nhe e Compute final LATIN SQARE statistics se sede dede ee e dede de de 860 NegTerm SumTotal 2 NumPositions NumSets NumRepsX 861 SSLT Total SS NegTerm 862 SSLPos SumTj NumPositionsX NumReps NegTerm 863 SSLSet SumTk NumSets NumReps NegTerm 864 SSLSens SumTi NumSensors NumReps NegTerm 865 SSLE SSLT SSLPos SSLSet SSLSens 866 DegFreeLPos NumPositions 1 867 DegFreeLSet NumSets 1 868 DegFreeLSens amp NumSensorsX 1 869 DegFreeLT NumPositionsX NumSets NumRepsX 1 870 DegFreeLEX DegFreeLT DegFreeLPos DegFreeLSet DegFreeLSens 871 MSLPos SSLPos DegFreeLPos 872 MSLSet SSLSet DegFreeLSet 873 MSLSens SSLSens 5 5 874 MSLE SSLE DegFreeLEX 875 FLPos MSLPos MSLE 876 FLSet MSLSet MSLE 877 FLSens MSLSens MSLE 878 END SUB 21 FWDCAL2 BAS March 28 1992 Page 22 SUB OutputToFile DIM 9 7 Year MID FileDate 1 2 Month MID FileDate 3 2
57. Summary Statistics A following summary statistics are produced by the program to aid in interpretation of the relative calibration test results Mean deflection of each sensor and the average for all sensors for drop set Mean standard deviation and coefficient of variation of each sensor for all drops 10 b FWDCAL Version 2 Program Manual February 1992 e Overall mean standard deviation and coefficient of variation of the deflection response of all sensors for all drops Mean standard deviation and coefficient of variation of all sensors by position in the stand Mean load for each drop set Mean standard deviation and coefficient of variation of the load for all drops The coefficient of variation is the standard deviation divided by the mean times 100 These statistics can be helpful in interpreting the results of a relative calibration test For example the systematic variation in the load between drop sets can be directly observed This can be the cause for the significance of drop set in the ANOVA The cause for some anomalous results can also be easily identified For example it is easy to detect if effect of one out of range sensor on the overall mean is causing another sensor to be indicated as out of range A test is performed on the significance of the variance between deflection sensors This test is performed to determine if the variation in the response of a sensor is much greater than
58. T 2 significant at the 5 level A repeat calibration is required to confirm PRINT 42 the need for gain adjustments Care should be taken to ensure that the PRINT 42 geophone bases are clean and firmly seated and that the stand is held PRINT 42 vertically with moderate downward pressure CASE NYY PRINT 42 Gain adjustments are indicated and sensor and stand position is statistically PRINT 42 significant at the 5X level A repeat calibration is required to confirm x PRINT 2 the need for gain adjustments Care should be taken to ensure that the PRINT 2 geophone bases are clean and firmly seated and that the stand is held PRINT 42 vertically with moderate downward pressure CASE ELSE END SELECT ELSE SELECT CASE 1 5 CASE YNN PRINT 42 No gain adjustments are indicated but drop set is statistically significant PRINT 2 at the 5X level This be due to warming of the buffers or consolidation PRINT 42 of pavement materials during the test Review the data carefully If anything PRINT 2 is suspect repeat the calibration after conditioning the FWD buffers with 50 PRINT 2 drops from height 3 If the defiections from the last 10 drops vary by more PRINT 2 than 1 mil 25 4 microns repeat the calibration at a new location CASE PRINT 2 Sensor and drop set are statistically significant at the 5 level but PRINT 2 gain adjustments are not indicated Revie
59. T a 1 END IF SELECT CASE a CASE CHR 73 page up CALL GainsPage1 Img PgDn to ANOVA Table Esc to exit results screens Img Img 2 PRINT Img CASE CHR 81 page down CALL LatinPage1 Img PgUp to Gains Table Esc to exit results screens Img Img 2 PRINT Img CASE CHR 27 EXIT DO END SELECT LOOP EXIT DO CASE EXIT DO CASE ELSE REDIM PUText 1 PUText 1 Please enter a Y only CALL PopupError 5 OldFTS END SELECT LOOP CLS END SUB 10 LEN Img LOCATE 25 40 LEN Img LOCATE 25 40 LEN Img LOCATE 25 40 360 362 FWDCAL2 BAS March 28 1992 11 SUB GainAdjustMsg SCREEN 0 WIDTH 80 25 CLS CALL NormalColor Year MID FileDate 1 2 Month MID FileDate 3 2 Day MID FileDate 5 2 MDYS Month DayS 8 dete see e e e e e e ede e de Geophone Gain Adj ustments PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT bm WHILE SPC 15 SHRP FWD Relative Calibration Gain adjustments SN FWDSN SPC 38 Calibration Date MDYS Data File Name file Ext Operator Operator Results of this test indicate the possible need to adjust then gains This should be confirmed with a repeat test Gain adjustment should be performed whe
60. VV IF ExitCode lt gt 0 THEN SPX INSTR WFile IF lt gt 0 THEN file LEFT WFile SPX 1 Ext LTRIMS RTRIMS RIGHTS WFile LEN WFile SP 1 ELSE file LTRIMSC RTRIMSCLEFT WFile 8 Ext END IF 14 557 538 539 540 i FWDCAL2 BAS March 28 EXIT DO END IF LOOP END SELECT SELECT CASE ExitCodeX determine next action CASE 71 home Item 1 CASE 79 end Item MaxI tem CASE 15 75 72 Shift Tab left arrow up arrow Item Item 1 CASE 9 13 77 80 Tab CR right arrow down arrow Item Item 1 CASE 68 F10 Continue IF file THEN REDIM PUText 1 PUText 1 A file name must be entered please try again CALL PopupError Item 3 ELSE ChkName FPath file Ext IF NOT Exist ChkName THEN REDIM PUText 1 PUText 1 File not found Please try again CALL PopupError file Ext ExitCodeX 0 Item 3 ELSE ExitCodeX 1 EXIT SUB END IF END IF CASE 65 F7 quit CLS PRINT PRINT PRINT Program Execution Terminated by User END CASE ELSE do nothing END SELECT IF Item lt 1 THEN Item 1 Item gt MaxItem THEN Item tem LOOP END SUB 15 1292 15 582 583 584 585 586 587 588 589 590 591 592 595 594 595 596 597 598 599 600 601 602 605 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627
61. WD Data File Selection screen Control Screen 2 it is convenient to start the program from the directory and or disk drive containing the FWD data file 26 FWDCAL Version 2 Program Manual February 1992 Control Screen 1 Select Analysis Type Control screen 1 is used to select the analysis type the program will run or can be used to exit the program after completing an analysis This screen is shown in Figure 6 To select the desired analysis press the up and down arrow keys to highlight the desired choice and then press the Enter key The Home and End keys can be used to jump to the first or last choice on the menu respectively The analysis types are Standard Analysis The standard analysis is for use in interpreting the results of routine relative calibration tests not conducted in conjunction with the Reference calibration test Replace a Geophone This analysis is used when one of the geophones is replaced or in the instance that the user wishes to exclude the effect of a specified geophone from the computation of the overall mean deflection response In this analysis the response of the replacement geophone is not included in the computation of the overall average mean response of all geophones Reference Relative Calibration This analysis is designed to be used for the relative calibration performed in conjunction with the SHRP Reference calibration procedure This analysis option computes and displays the new
62. at the 5X level A repeat calibration after conditioning the FWD PRINT buffers with 50 drops at height 3 is required to confirm the need for gain PRINT adjustments If deflections for the last 10 drops vary by more than 1 mil u PRINT 25 4 microns repeat the calibration at a new location CASE YNY PRINT Gain adjustments are indicated Set and stand position are statistically PRINT significant at the 5 level A repeat calibration after conditioning the PRINT buffers with 50 drops at height 3 is required to confirm the need for gain PRINT adjustments When doing the calibration extra care should be taken to seat PRINT the geophones properly and hold the stand vertically with a moderate level PRINT of downward pressure If deflections for the last 10 drops vary by more than PRINT 1 mil 25 4 microns repeat the calibration at a new location CASE YYY PRINT Gain adjustments are indicated Set sensor and stand position are PRINT statistically significant at the 5 Level A repeat calibration is required PRINT after conditioning the FWD buffers with 50 drops at height 3 for adjustments PRINT When doing the calibration extra care should be taken to properly seat the PRINT geophones and hold the stand vertically with a moderate level of downward PRINT pressure 1f deflections for the last 10 drops vary by more than 1 PRINT mil 25 4 microns repeat the calibration at a new location
63. ated the interim calibration factors shall be entered into the FWD computer before proceeding with relative calibration A sample reference calibration setup screen for the Dynatest FWD with version 10 or version 20 software is given in Figure 1 The information in Figure 1 can also be used as the basis for setup of Dynatest FWDs running version 25 and higher software A complete summary of the data to be recorded is given in Table 1 Before beginning to perform the calibrations FWD specific information should be recorded via printouts from the FWD data acquisition program screens e g showing the deflection sensor serial numbers and calibration factors load cell serial number calibration factor and sensitivity and voltage screens from the Dynatest software which have been annotated with the date and FWD identification information i e FWD model and serial number Locate the calibration data acquisition system as close as possible to the FWD computer so that the two systems operators will be able to converse easily Load the reference calibration software FWDREFCL into the reference system computer Directions for performing reference calibration using this software are provided in the FWDREECL User s Guide Before doing any calibrations verify that the computers for the FWD and the reference data SHRP FWD CALIBRATION PROTOCOL April 1993 Reference Calibration Test UNITS lbf mil inch kPa mu mm Temperature Fahrenheit Ce
64. creen 3 Gain Change Instructions This screen is always displayed if one of the means ratio for a sensor is outside of the tolerance limit The user is not given a choice of displaying this screen To exit this screen the user must hit any key The contents of this screen are shown in Figure 12 Output Screen 4 Average New Gain Factors This screen is only displayed for the results of a Relative Reference type of analysis This screen shows the computed new relative gain factors for each of the three repeat relative calibration tests and the average of the tests An example is shown in Figure 13 32 FWDCAL Version 2 Program Manual February 1992 SHRP Relative Calibration Gains Tabie FUD SN 8882 8061 Calibration Date 85 31 91 Bata File Name 61053191 H8C3 Data Set 1 of 1 perator SMITH Sensor Exitisting Meaus Neu Ost nf Limit Sensor 8 S H Gain Factor Ratio Relative Gain Tolerance Range aB11 8 362 NO 9 4 8 986 YES 8015 8 998 8638 8 993 YES 8 8 1 848 986 2 838 958 3 833 983 4 034 5 5 835 393 3813 3 994 ri B3 993 8818 995 9988 992 NO 9985 9 992 NO OC M Warning At one sensor outside the tolerance limit Verify these results with an additional test gt RESULTS INDICATE THAT THE SENSOR GAINS SHOULD BE RESET to ANOVA Table Esc to exit results screens Figure 10 Gains table output screen
65. ded tip of the LVDT Use non lubricating contact cleaner in a pressurized can to spray cleaner into the bearing sleeve until the tip goes in and out without noticeable friction Check by working the tip in and out The stroke should be smooth without bumps If the LVDT cannot be made to operate smoothly do not continue with the calibration Use the micrometer calibrator to calibrate the LVDT do this the LVDT should first be positioned in the calibrator and set to the null point zero voltage output with the 7 SHRP FWD CALIBRATION PROTOCOL April 1993 micrometer set to 5 mm micrometer should then be advanced slightly beyond 7 mm and returned to the 7 mm mark Verify that the MetraByte board reads within 30 bits of 2000 bits If necessary adjust the Gain knob on the 2310 signal conditioner in increments of 0 1 for instance from a setting of 1 50 x1 to a setting of 1 40 x1 to achieve the required reading The LVDT voltage output and the micrometer reading 7 mm should be recorded The micrometer should be moved in 0 5 mm increments to a final reading of 3 0 mm with the micrometer reading and LVDT voltage output recorded at each 0 5 mm step Turn the barrel of the micrometer in one direction only to avoid errors due to backlash Analyze the resulting data using a linear regression to determine the coefficient m in the equation m X b where Y is the position of the LVDT tip in microns as measured by
66. djustment factor should be less than 0 0020 If a larger standard error is obtained for any sensor the reference calibration for that sensor should be repeated 2 Enter the new calibration factors for all sensors load and deflection transducers in the 10 SHRP FWD CALIBRATION PROTOCOL April 1993 FWD Field Program before continuing with the relative calibration The new calibration factor for the FWD load cell is a final calibration factor while the new calibration factors for the deflection sensors are interim factors which will be further refined by doing relative calibration RELATIVE CALIBRATION PROCEDURE General Background Relative calibration of the FWD deflection sensors is used to ensure that all sensors on a given FWD are in calibration with respect to each other As such it serves as the final step in the overall FWD calibration process and as a quick means to periodically verify that the sensors are functioning properly and consistently Relative calibration uses the relative calibration stand supplied by the FWD manufacturer The sensors are stacked vertically in the stand one above another so that all sensors are subjected to the same pavement deflection Relative calibration assumes that the overall mean deflection as determined from simultaneous measurements by the full set of deflection sensors yields an accurate estimate of the true deflection This assumption requires that the deflection sensors must have
67. e Final Calibration Computation worksheet see Appendix C Distribution of this report shall be as follows Original retained by FWD operator for submission to his agency LTPP Regional Engineer for LTPP FWDs One copy transmitted to LTPP Division Office within one week of calibration copy retained on file by calibration center for a period of at least three years The diskettes on which the reference and relative calibration data are stored should be kept in the FWD It is recommended that labeled backup copies be kept on file with the calibration report at the office out of which the FWD is operated For the LTPP FWDs additional backup copies of the calibration diskettes are to be kept on file at the LTPP Regional Office When relative calibration is done alone e g as a monthly calibration check the relative calibration report will consist of all printouts from the FWDCAL2 software annotated as necessary to explain any problems which might have been encountered 17 SHRP FWD CALIBRATION PROTOCOL April 1993 APPENDIX A REFERENCE CALIBRATION EQUIPMENT AND FACILITIES I Facilities Indoor space with easy access for FWD and towing vehicle e level floor large enough so that both the FWD trailer and the towing vehicle can sit level during the test and be enclosed indoors reasonably constant temperature between 50 and 100 and humidity 40 90 percent heated but not necessarily air conditioned
68. e noise is of concern before rejecting the calibration e Standard deviations for the five readings at any drop height that differ by more than a factor of three between the reference system data set and the FWD data set e Standard error of the adjustment factor see Reference Calibration Data Analysis in excess of 0 0020 Should any of these conditions occur the calibration test for the deflection sensor must be repeated after identifying the source of the problem and correcting it Reference Calibration Data Analysis Analyze the data as follows calculations are done automatically by the FWDREFCL software A Perform a least squares regression forced through zero for all of the data for each measurement device i e 20 pairs of data per test 5 replicates at each of 4 load levels The result of this regression will be the coefficient for an equation of the form Y m X where Y represents the response of the reference system X represents the response of FWD measurement device and m is the slope of the regression line Both X and should be measured in the same system of units B The coefficient m determined in step A represents the adjustment factor for the calibration factor in the FWD Field Program The new calibration factor is computed by multiplying the former calibration factor by the coefficient m from step This is listed as the new calibration factor on the FWDREFCL report C The standard error of the a
69. e relative Latin square experiment Design is BE tuu D where Observed deflection response for sensor i in position for drop set k and repeat drop number Effect of stand position J Effect of drop set 7 Effect of sensor i random error The following restriction are imposed on the effects as follows NumPos NumSens 2 0 1 k 1 i l where NumPos Number of positions in the stand The x are assumed to have a normal distribution with means 3 Big B and with a common variance The following three hypothesis are tested with the Latin Square ANOVA es 1 Q QOnumPos 0 Atieast one is not equal to zero i e position is significant 2 By B 9 At least one is not equal to zero i e set is significant 3 Tues 0 At least one is not equal to zero i e sensor is significant FWDCAL Version 2 Program Manual February 1992 The sum of squares identity can be written as SST SSp 554 SSs SSE 4 where SST Total sum of squares SSp Position sum of squares SSd Drop Set sum of squares SSs Sensor sum of squares SSE Error sum of squares Since the position subscript j is dependent upon the sensor number subscript i and drop set subscript k it is convenient to sh
70. ee dede de de dee de e dede k dede de dede e Cochran test results dede jede de dede dede de dede ie IF ProblemExist 1 THEN PRINT 42 Results of Cochran Test on Significance of Variance Between Geophones PRINT 42 PRINT 2 The variance for Sensor No BigDef is significantly larger than PRINT 42 the other sensors This could be a result of incorrect seating of the PRINT 42 sensor in the stand OR an indication that this sensor is bad and needs PRINT 42 to be replaced Please confirm with additional tests END IF PRINT 42 CHR 12 1 04e Je ede eje de de de de Data Replay kkkkkkkkkkkkkkkkkkkkkkkkkkkkk PRINT 2 SPC 23 Relative Calibration Input Data PRINT 2 FWD SN FWDSN SPC 37 Calibration Date MDYS PRINT 42 Data File Name file Ext SPC 32 Data Set SCX of SetCount PRINT 2 Operator Operator PRINT 42 PRINT 42 Set Drop Load Deflections 0 001 inches mils PRINT 2 tbf Df1 Df2 Df3 0 4 0 5 0 6 Df7 PRINT 2 40 HH HER BH BRE Lin 1 Set 1 FOR W 1 NumSets NumReps drop Set 1 5 PRINT 2 USING t0 drop LoadData OutDef 1 OutDef 2 OutDef 3 OutDef WA 4 OutDef WX 5 OutDef 6 OutDef WX 7 25 1139 1140 1141
71. eep the measurements derived from the deflection sensors equivalent In the relative calibration procedure all deflection sensors are placed in a stand which is held vertical on a point located near the load plate so that all sensors are subjected to the same deflection The measurements consist of subjecting the sensors to a five drop load sequence then rotating the positions of the sensors in the stand placing the stand on the same point and repeating the drop sequence This process is repeated until all sensors have been tested in each position in the stand The position of the sensors in the stand are rotated to serve as a check on proper conduct of the test and cancel out any effect of stand position on the results The most basic analysis of the data collected in a relative calibration test consists of the following 1 Calculating the ratio of overall mean deflection of all sensors for all drops to the mean deflection of each sensor for all drops This is called the means ratio 2 Computing the new gain value which is the product of the means ratio times the existing gain value gj FWDCAL Version 2 Program Manual February 1992 In addition the following statistical analyses are used as aids in evaluating the validity of the relative calibration test and in investigating anomalous results Latin Square analysis of variance ANOVA This determines the statistical significance of sensor set and position on the test re
72. eer after verifying with additional tests END IF IF Jnum1X gt 0 THEN PRINT 32 PRINT 42 RESULTS INDICATE THAT THE SENSOR GAINS SHOULD RESET END IF IF RepSensX 0 THEN PRINT 2 PRINT 42 15 PRINT 42 repm2 USING NewGain SC 5 lt END IF PRINT 42 PRINT 2 IF Jnumi gt 0 THEN 9 se de dee dede fe Geophone Gain Adjustments kkk kkkhh kk kkk kkk kk PRINT 2 SPC 16 SHRP FWD Relative Calibration Gain adjustments PRINT 42 PRINT 2 Results of this test indicate the possible need to adjust the gains PRINT 42 This should be confirmed with a repeat test PRINT 2 PRINT 2 Gain adjustment should be performed when the New Gain Factors for two PRINT 2 independent calibrations are within 0 002 of each other PRINT 2 PRINT 2 Gain adjustments should be made ONLY to the out of range geophone s PRINT 42 PRINT 42 After adjusting any gain setting the relative calibration test must B 22 TOLS S a FWOCAL2 BAS March 28 1992 Page 23 PRINT 42 repeated to confirm that all sensors are within tolerance END IF PRINT 42 PRINT 2 PRINT 2 CHR 12 de dede sede e eje de defe de de ke e ded hee Lat i n Squa re Des i gn Ana 5 1 Output efe de de ede dede dee ke ke dede deje PRINT 42 5 12 SHRP FWD Relative Calibration Latin Square ANOVA Table PRINT 2 FWD SN FWDSN SPC 37 Calibration Date MDYS PRINT 2 Data F
73. ensor No 835 Sensor No 3813 Sensor No 83 Replacement Quit Program Enter Selection 1 1 Home End Figure 8 Select replaced geophone control screen Output Path and File Name Hs LANGUAGENBAS ICNGEBNCHNRAJS61853191 CS3 Display calibration results on screen Figure 9 Display results control screen 31 FWDCAL Version 2 Program Manual February 1992 Output Screen 1 Gains Table If a Y es is selected to display the results on the screen in field 2 on Display Results Control Screen then the Gains Table is displayed on the screen In this screen the user has the option of press lt Page Down or lt PgDn gt to display the ANOVA Table or lt Esc gt to exit the output screens An example of the Gains Table screen is shown in Figure 10 An explanation of the information and summary of the user messages presented in the Gains Table is discussed in the program output section of this document Output Screen 2 ANOVA Table The results of the ANOVA is displayed after the lt PgDn gt key is pressed in the Gains Table screen In this screen the user has the option of pressing lt PgUp gt or lt Page Up to return to the Gains Table screen or lt Esc gt to exit from the result table screens An example of the ANOVA Table screen is shown in Figure 11 An explanation of the information and summary of the messages presented in the ANOVA Table is discussed in the program output section of this document Output S
74. er instructions Sensor is statistically significant at the 596 level but gain adjustments are not indicated Test results should be carefully reviewed If anything appears suspect repeat the calibration Otherwise these results are acceptable FWDCAL Version 2 Program Manual February 1992 Table 2 Messages when gain ratios are within the tolerance range Contd Gains do not needed to be adjusted but stand position is statistically significant at the 596 level This may be caused by failure to keep the stand vertical or improper seating of the geophones In the future care should be taken to ensure that the geophone bases are clean and well seated and the stand is kept vertical with moderate downward pressure Sensor and stand position are statistically significant at the 590 level but gain adjustments are not indicated Review calibration results carefully If anything appears suspect repeat the calibration taking care to ensure that geophone bases are clean and properly seated and the stand is kept vertical with moderate downward pressure 21 FWDCAL Version 2 Program Manual February 1992 Table 3 Messages when a gain ratio is outside of the tolerance range sen ros Message ooo Gain adjustments are indicated and drop set is statistically significant at the 546 level Set significance may be due to warming of the buffers or consolidation of pavement materials during the test A repeat calibratio
75. es PRINT Version 1 00 TABLE 6 PRINT IF Edition lt gt 10 AND Edition lt gt 20 THEN PRINT Version 10 or 20 of Dynatest Field Program Not Used ELSEIF Numeftectors lt gt NumSensors amp THEN PRINT Not Using 7 Deflectors ELSEIF ActiveDrops lt 46 THEN PRINT Less Than 46 Active Drops in Sequence ELSEIF ImitNumPeaks MOD NumDrops gt 0 THEN PRINT Not Using 5 Repeat Drops END IF PRINT PRINT END END SUB FWDCAL2 BAS March 28 1992 Page 7 200 SUB CheckHeader InitNumPeaks InitNumWHBlocksX ExitCodeX STATIC 201 CALL ReadNextLine DataType LineLength 202 SELECT CASE LineCounter amp 203 CASE 1 204 FileWidthX VALC MIDS LineData 2 4 205 IF FileWidth 32 THEN 206 English False 207 ELSE 208 English True 209 END IF 210 FileDate MID LineData 14 6 Data collected on FileDate 211 Edition VAL MID LineData 31 2 212 IF Edition lt gt 10 AND Edition lt gt 20 THEN CALL BadFile 213 CASE 2 214 NumDef lectors VAL LEFT LineData 1 215 IF Numeflectors lt gt NumSensors THEN CALL BadFile 216 FWDSN MID LineData 9 8 217 CASE 3 TO 10 22 TO 29 31 32 54 TO 36 218 CASE 11 TO 20 deflector 1 to 10 219 SensorNumberX VAL MID LineData 2 2 220 SerialNumX LineCounter amp 10 VAL MID LineData 4 5 221 RelGain LineCounter amp 10 VAL MID LineData 10 5 222 CASE 21 operator 223 Operator LTRIMSCRTRIMS LineData
76. ese tables a Y indicates the effect was significant The message shown in Table 2 instructs the user to contact the supervising engineer if the situation occurs where the means ratios are within the tolerance limits for all sensors and sensor set and position are all significant This unlikely situation can occur when the mean square error term has a very small value less than 1 0 x 10 The data set should be reviewed for potential anomalies It can be expected that in this situation the coefficient of variation for all deflections will be less than 0 5 If very good repeatability low coefficient of variation is found between sensors and all measurements then the calibration should be accepted as valid and no changes made to the gain factors An example ANOVA Table output produced by the program is shown in Figure 3 19 FWDCAL Version 2 Program Manual February 1992 Table 2 Messages when gain ratios are within the tolerance range Set sen os Y Y N No gain adjustments are indicated but drop set is statistically significant at the 5 level This can be due to warming of the buffers or consolidation of pavement materials during the test Review the data carefully If anything appears suspect repeat the calibration after conditioning the FWD buffers with 50 drops from height 3 If the deflections from the last 10 drops vary by more than 1 mil 25 4 microns repeat the calibration at a new locati
77. esting machine In column C subtract the tare weight of the upper bearing block from the loads in column B In column D enter the MetraByte board 29 SHRP FWD CALIBRATION PROTOCOL April 1993 readings in bits Note that the readings are negative In columns E F G and H calculate V v3 V and V5 respectively where V represents the readings in column D Use the spreadsheet regression utility to calculate a linear regression of corrected load as the Y variable versus bits as the X variable The regression should be forced through zero yielding an equation of the form Y m V where Y is the corrected load column C V is the voltage column D and m is the slope of the line of best fit The coefficient m should be approximately 10 pounds per bit Use the regression utility to calculate a fifth degree polynomial regression of the form A V A V A A V where the coefficients A are determined by the regression Evaluate the polynomial solution to the following criteria 1 The standard error of the Y estimate should be less than 50 pounds 2 The standard error of each of the coefficients should be small with respect to the coefficient Generally speaking the coefficient should be at least a factor of ten larger than its standara error For instance if the coefficient A is 0 15 its standard error should be 0 015 or smaller If this is not the case the regression coefficient is
78. example from a setting of 5 50 x100 to 5 40 x100 to achieve the required reading Release the load Record the gain setting Note When the load is released the MetraByte board will not read exactly zero because it was zeroed without the upper bearing block in place Do not rezero the signal conditioner at this point Apply load at a rate no faster than 1 000 pounds per minute Record the MetraByte board readings at 1 000 pound intervals up to a maximum load of 20 000 pounds While releasing the load record a reading at 10 000 pounds and at zero load Remove the upper bearing block and if necessary adjust the Trim knob on the signal conditioner until the MetraByte board reads bits Push and hold the Cal switch in the position and record the reading Repeat for the B position Set the Auto Balance switch to OFF and again record the unbalanced zero voltage This reading should be within three bits of the earlier reading If it is not repeat the calibration procedure from step 4 be sure that the load cell is centered in the testing machine and be sure to repeat the 20 000 pound preloading procedure in step 6 DATA ANALYSIS Using a spreadsheet utility program such as Lotus 1 2 3 enter the results of the calibration In column A enter the nominal loads registered by the universal testing machine 1 0 1000 2000 etc In column B correct these loads to the NIST traceable loads based on the certificate of calibration for the t
79. first been subjected to the reference calibration procedure Some FWDs have fewer than or more than seven active deflection sensors If they do these procedures should be modified to calibrate the actual number of active sensors in use on the FWD Equipment FWD relative calibration stand with as many positions as the number of active deflection sensors For purpose of illustration a seven position stand is assumed herein FWD relative calibration software FWDCALD2 and documentation General Procedure The process involves rotation of the seven deflection sensors through the seven positions in the calibration stand Each combination of sensors and levels is considered a set and thus there are seven sets of data The test point is conditioned before beginning the calibration procedure to reduce the possibility that set will be significant in the data analysis The 11 SHRP FWD CALIBRATION PROTOCOL April 1993 required order of movement of the sensors is shown in Table 2 Spare deflection sensors do not have to be calibrated until they are in active use Table 2 Relative Calibration Sensor Positions by Set Level in Sensor Deflection Sensor Number the Stand Stand Set 1 2 3 4 5 6 1 2 3 4 5 6 7 B 2 3 4 5 6 7 1 3 4 5 6 7 1 2 D 4 5 6 7 1 2 3 E 5 6 7 1 2 3 4 6 7 1 2 3 4 5 7 1 2 3 4 5 6 Bottom Note The rotation must be done as above in order for the software FWDCAL2 to work
80. han 1 mil 25 4 microns repeat the calibration at a new location Figure 3 Example print of output file of the ANOVA Table 14 FWDCAL Version 2 Program Manual February 1992 Relative Calibration Input Data FWD SN 8002 061 Calibration Date 05 31 91 Data File Name 61053191 RC3 Data Set 1 of 1 Operator RICK SMITH Set Drop Load Deflections 0 001 inches mils lbf Df1 Df2 Df5 Df6 1 1 22 064 18 12 18 22 18 05 18 00 18 04 18 09 18 10 1 2 22 088 18 12 18 13 18 05 17 96 18 04 18 09 18 10 1 3 22 032 18 50 18 59 18 47 18 46 18 54 18 52 18 53 1 4 22 032 18 07 18 09 18 05 17 96 18 04 18 09 18 10 1 5 22 088 17 99 17 97 17 96 17 83 17 91 17 91 17 98 2 1 22 080 18 63 18 68 18 60 18 58 18 54 18 61 18 62 2 2 22 048 18 24 18 30 18 26 18 17 18 12 18 22 18 23 2 3 22 088 17 95 18 01 17 96 17 83 17 83 17 95 17 93 2 4 22 040 18 03 18 09 18 05 17 92 17 95 18 00 18 06 2 5 22 008 18 29 18 38 18 30 18 17 18 21 18 30 18 32 3 1 22 048 18 07 18 22 18 09 18 08 18 04 18 09 18 15 3 2 22 136 18 58 18 80 18 68 18 67 18 67 18 74 18 71 3 3 21 984 18 29 18 51 18 34 18 33 18 29 18 39 18 36 3 4 22 152 17 99 18 18 18 05 18 00 18 00 18 09 18 06 3 5 22 048 17 99 18 18 18 05 18 00 18 00 18 04 18 10 amp 1 22 048 18 54 18 63 18 55 18 58 18 50 18 61 18 58 4 2 22 104 18 71 18 84 18 77 18 75 18 71 18 79 18 75 4 3 22 000 18 24 18 34 18 22 18 25 18 21 18 35 18 28 4 4 22 072 18 37 18 47 18 39 18 42 18 42 18 48 18 45 4 5 21 992 18 16 18
81. high degree of precision can be attained however only if this calibration procedure is followed exactly It is essential that the reference load cell be calibrated using a universal testing machine that is properly maintained and accurately calibrated FREQUENCY OF CALIBRATION Calibration of the reference load cell should be performed at least once per year It should also be performed immediately after any of the six Allen head screws that attach the load measurement links to the upper or lower plates of the reference load cell are loosened Calibration would also be necessary if the load cell fails to pass the unbalanced zero test within 5 percent as detected by the FWDREFCL program EQUIPMENT Universal testing machine A static testing machine hydraulic or screw powered with a load capacity of 120 000 pounds or more should be used for the reference load cell calibration Although the reference load cell will only be calibrated to a capacity of 20 000 pounds the higher capacity of the testing machine assures that the test frame will be adequately rigid The testing machine should have several load ranges among them 0 20 000 pound range slightly higher ranges such as 0 24 000 pounds etc would be acceptable Care must be taken to avoid overloading the reference load cell during its calibration Note Do not use a servo controlled closed loop testing system such as a MTS machine for this purpose In general such equipment
82. his analysis deflection is the dependent variable and sensor number position and set are the three main factors The three hypotheses that may be tested are Sensor number is a significant source of error Data set number is a significant source of error H Position in the stand is a significant source of error Through the use of hypothesis testing it is possible to determine whether random error due to sensor number due to position in the calibration stand and due to set number are statistically significant The only factor that should result in a change in the deflection sensor calibration factors 15 sensor number If the random error due to sensor number is found to be statistically significant then the 14 SHRP FWD CALIBRATION PROTOCOL April 1993 calculated adjustments in the calibration factors for each sensor should be made If a change is made in the calibration factor for one sensor then the calibration factors for all sensors should be changed in accordance with the calculations If position in the stand is statistically significant it is likely that the stand was not held vertical throughout all of the sets during the test Or a connection in the stand may have been loose The problem should be corrected and the test should be repeated If set is statistically significant there may have been a systematic change in the properties of the pavement materials for instance due to compaction or liquefaction The
83. ical contributions were provided by Dr Lynne Irwin Cornell University and Consultant to SHRP Version 1 of the program was written by Mr Scott Rabinow of PCS LAW Engineering Beltsville Maryland Version 2 of the program was written by Mr Raj Basavaraju and Mr Gary E Elkins of Nichols Consulting Engineers iii Table of Contents Backseround Wu a e Cee REC n b Program Description PWD Data Guns Latin Square ANOVA Summary Statistics 94 94 Program Gains Table dee OE X p e adieu dC SOLVE SE eaa ANOVA Ves EV Eie UO ADM Rd didt Deflection Input Data Summary vous eo eR SWR d QUE XR eR Ed Program Operation Program Installation and Starting Control Screen 1 Select Analysis Control Screen 2 FWD Data File Selection Control Screen 3 Select Geophone Replaced Control Screen 4 Display Results on Screen Output Screen 1 Gains Table Output Screen 2 ANOVA
84. ignPosition Index Posit STATIC Count 0 FOR i Index TO NumSensorsX Posit i 1 Index 1 NEXT i FOR i IndexX 1 TO 1 STEP 1 Count Count 1 PositX Count NumSensors i 1 NEXT 1 END SUB FWOCAL2 BAS March 28 1992 Page 3 FWDCAL2 BAS March 28 1992 4 SUB AvgGainToFile FOR 1 1 TO NumSensorsX AvgNewGain i NewGain 1 1 NewGain 2 1 NewGain 3 130 3 NEXT iX 1 1 Sl de dee de dede de Year MID FileDate 1 2 Month MID FileDate 5 2 Day MID FileDate 5 2 MDY Month Day Year 1 Aek kekk kek dede e Geophone Calibration Sensor kkk kk kk kkkh kkk PRINT 42 SPC 14 SHRP FWD Relative Calibration Average Gains Table PRINT 2 FWD SN FMDSN SPC 38 Calibration Date PRINT 42 Data File Name file Ext SPC 12 Average Means and Gains for 3 data Sets PRINT 2 Operator Operator PRINT 42 PRINT 2 Sensor Existing Relative Gain PRINT 42 Sensor S N Gain Factor Set 1 Set 2 Set 3 Average PRINT 22 8 18 HHH HHH FOR S 1 TO NumSensorsX PRINT 2 USING 18 SX SerialNumX SX RelGain S NewGain 1 SX NewGain 2 5 NewGain 3 SX AvgNewGain S NEXT END SUB FWDCAL2 BAS March 28 1992 Page 5 SUB AvgGainToScreen CLS
85. ile Name file Ext SPC 32 Data Set 5 of SetCount PRINT 2 Operator Operator PRINT 2 PRINT 2 Variation Sum of Degrees of Mean Computed Critical PRINT 2 Source Squares Freedom Square f f PRINT 42 Data TAE HHHH HE HH HH IF FLPos gt 1000 OR FLSet gt 1000 OR FLSens gt 1000 THEN Data THE HR PRANAN IHE 1HP END IF PRINT 2 USING Data Position CSNG SSLPos DegFreeLPos CSNG MSLPos CSNG FLPos CritFLPos PRINT 2 USING Data CSNG SSLSet DegFreelSetX CSNG MSLSet CSNG FLSet CritFLset PRINT 2 USING Data Sensor CSNG SSLSens DegFreeLSens CSNG MSLSens CSNG FLSens CritFLSens PRINT 2 USING Data Error CSNG SSLE DegFreeLEX CSNG MSLE PRINT 2 USING Data TOTAL CSNG SSLTZ DegFreeLT PRINT 42 IF FLSet CritFLset gt 0 THEN IF FLSens CritFLSens gt 0 THEN FLPos CritFLPos gt 0 THEN LSAM YyY ELSE LSAMS END IF ELSE IF FLPos CritFLPos gt 0 THEN LSAM ypy ELSE LSAM YNN END IF END IF ELSE FLSens CritFLSens gt 0 THEN IF FLPos CritFLPos gt 0 THEN LSAM NYY ELSE LSAM END IF ELSE IF FLPos CritFLPos gt 0 THEN LSAMS NNY ELSE LSAMS NNN END IF END IF END IF IF FLSens CritFLSens lt 0 AN
86. in utility should be installed according to the Lotus directions Defaults in 27 SHRP FWD CALIBRATION PROTOCOL April 1993 Lotus 1 2 3 should be set as follows e Default directory 9 Auto execute macros on Auto attach add in 41 C LOTUS WYSIWYG See the Lotus User s Manual for instructions regarding setting the defaults If the program is correctly installed and set up the data analysis will be run a listing of the data will be produced and graphical output will be printed automatically A demonstration version of LDCELCAL is available to use with Lotus 1 2 3 to verify that your computer system can interact properly with the program CALIBRATION PROCEDURE l Attach the cable from the signal conditioner to the reference load cell turn on the signal conditioner and allow the system to warm up for at least 15 minutes Attach the cables connecting the signal conditioner to the computer Attach the push button trigger in the blue terminal box of the MetraByte data acquisition system Turn on the computer and the printer If an hydraulic universal testing machine is used turn the pump on and allow it to warm up for 15 minutes Place a wood aluminum bearing block with no rubber pad in the center of the testing machine platen Place the reference load cell on top of the bearing block with the three steel pads down i e in contact with the top surface of the lower bearing block Place the second bearing bl
87. k CASE ELSE EXIT DO END SELECT END IF LOOP IF DropCountX lt gt CritNumDropsX THEN CALL BadFile END IF CLS CALL NormalColor IF Se tountX gt 1 AND 1 S THEN 644 Input data file has STR SetCountX data sets SM1 LEN SMIS LOCATE 2 40 5 1 2 PRINT 5 15 SM2 Analysis will be performed sequentially on each set SM2 1 5 2 LOCATE 13 40 SM2 2 PRINT 5 2 SLEEP 4 ELSEIF SetCount gt 1 AND Analysis G THEN SM1 Input data file has STR SetCountX data sets 5 1 LEN SM1 LOCATE 12 40 5 1 2 PRINT 5 1 SM2 Analysis will be performed sequentially on each set SM2 LEN SM LOCATE 13 40 SM2 2 PRINT 5 25 SLEEP 4 ELSEIF SetCount lt 3 AND Analysis R THEN SM1 Not enough data sets to run Reference Relative Calibration Analysis SM1 LEN SM1 LOCATE 12 40 5 1 2 PRINT SM1 SM2 Please select correct analysis type from the menu SM2 LEN SM2 LOCATE 13 40 SM2 2 PRINT SM2 SLEEP 4 GOTO Start END IF OExt C Analysis RIGHTSCExt 1 Output FPath file OExt OPEN Output FOR OUTPUT AS 42 IF Analysis OR Analysis THEN CALL GetSensorNum END IF CALL StartAnalysis IF SetCount 3 AND Analysis THE CALL AvgGainToFile CALL AvgGainToScreen END IF IF Jnum1 gt 0 Analysis lt gt R THEN CALL GainAdjustMsg END IF CLOSE GOTO Start CALL Quit SUB Ass
88. locate the FWD to a different pavement In general a concrete pavement on a relatively weak subgrade will yield the required deflection In most cases the reference calibration test pad should be usable for relative calibration 6 Warm up the FWD rubber buffers and condition the test point by repeating a sequence of ten drops until the loads and deflections that are registered are nearly uniform The deflections in a sequence of ten drops should not be showing a steadily increasing or decreasing trend liquefaction or compaction is indicated by the warm up data relocate the FWD to another pavement 7 Lower the FWD loading plate DO NOT raise the loading plate or move the FWD during the relative calibration testing This will assure a constant distance between the center of the load plate and the base of the sensor stand 8 For each set make two seating drops no data recorded followed by five replicate drops for which data is recorded while holding the stand in a vertical position With seven sets and 5 replicate drops data for a total of 35 drops is required see Figure 2 Relative Calibration Data Analysis A three way analysis of variance should be used to evaluate the data This will partition the variance into four sources 1 that due to sensor number 2 that due to position in the calibration stand 3 that due to set and 4 that due to random error of measurement This analysis is performed by the FWDCAL2 software In t
89. n after conditioning the FWD buffers with 50 drops from height 3 is required to confirm the need for gain adjustments If the deflections from the last 10 drops vary by more than 1 mil 25 4 microns repeat the calibration at a new location Gain are indicated Sensor and drop set are statistically significant at the 590 level A repeat calibration after conditioning the FWD buffers with 50 drops at height 3 is required to confirm the need for gain adjustments If deflections for the last 10 drops vary by more than 1 mil 25 4 microns repeat the calibration at a new location Gain adjustments are indicated Set and stand position are statistically significant at the 590 level repeat calibration after conditioning the FWD buffers with 50 drops at height 3 is required to confirm the need for gain adjustments When doing the calibration extra should be taken to seat the geophones properly and hold the stand vertically with a moderate level of downward pressure If deflections for the last 10 drops vary by more than mil 25 4 microns repeat the calibration at a new location Gain adjustments are indicated Set sensor anc stand position are statistically significant at the 590 level A repeat calibration is required after conditioning the FWD buffers with 50 drops at height 3 for adjustments When doing the calibration extra care should be taken to properly seat the geophones and hold the stand vertically with a m
90. n the new gain factors from two independent calibrations are within CHR 241 0 002 of each other Gain adjustments should be made ONLY to the out of range geophone s After adjusting any gain setting the relative calibration test must repeated to confirm that all sensors are within tolerance Press any key to continue bml LEN bm LOCATE 25 40 bml 2 PRINT bm INKEYS WEND END SUB B 11 FWDCAL2 BAS March 28 1992 Page 12 SUB GainsPage1 SCREEN 0 WIDTH 80 25 CLS Year MID FileDate 1 2 Month MID FileDate 3 2 Day MID FileDate 5 2 MDY Month Year dete de dede dede de defe de Geophone Calibration PRINT SPC 18 SHRP FWD Relative Calibration Gains Table PRINT FWD SN FWDSN SPC 37 Calibration Date MDY PRINT Data File Name file Ext SPC 32 Data Set SCA of SetCountA PRINT Operator Operator PRINT PRINT Sensor Existing Means Out of Limit PRINT Sensor S N Gain Factor Ratio Relative Gain Tolerance 2X Range PRINT 18 HHH 8 8HE HHH X FOR SX 1 NumSensorsX PRINT USING 8 5 SerialNumX SX RelGain S MeansRat SC 5 NewGain SC 5 01 5 RANSCSA NEXT SX PRINT IF Jnum1X gt 0 THEN PRINT Warning A
91. nded The program must be run under the DOS environment Two copies of the program should be made on two other disks to serve as a working and intermediate backup The program distribution disk should be stored with other computer software backups For a computer with a hard disk the installation process consists of copying 25 FWDCAL Version 2 Program Manual February 1992 the program onto the desired directory or subdirectory This can be done by using the change directory command to make the destination directory the current directory Then issuing the DOS command COPY drive FWDCAL2 EXE V where drive corresponds to the floppy disk drive containing the disk with the FWDCAL2 EXE program file The V switch verifies that the program was properly copied The program can be started by typing lt Drive gt lt Path gt FWDCAL2 where Drive Specifies the name of the hard disk drive or floppy disk drive containing the FWDCAL2 EXE program file Path Specifies the route the computer is to follow through the directory structure to locate the directory which contains the FWDCAL2 EXE program file If the current directory contains the FWDCAL2 EXE file or if the directory containing the program is included in the PATH statement in the AUTOEXEC BAT file the program can be started by typing FWDCAL2 at the command prompt Since the directory that the program is started from becomes the default directory in the F
92. ndent calibrations are within 38 882 of each other Gain adjustments should be made ONLY to the out of range geophone s After adjusting any gain setting the relative calibration test should be repeated to confirm that all sensors are within tolerance Fress any key to cantinue Figure 12 Sensor gain adjustment message SHRP Relative Calibration fiverage Gains Table FU SH 8882 65 Calibration Date 85 08 91 Bata File Name TEMPS3SET BCi Average Means and Gains for 3 data Sets Operator RICK SMITH Sensnr Existing Meu Relative tain Sensor S N Gain Faetar Set 1 Set Z Set 3 Average 848 8 336 331 9331 333 391 835 8 558 987 987 34 38 833 383 992 952 992 2532 834 398 931 1991 334 Sdi 535 893 981 331 981 soak 3813 894 2991 331 951 837 393 893 393 333 993 Press any to continue Figure 13 Reference relative calibration average new gain factor screen 34 FWDCAL Version 2 Program Manual February 1992 Function Keys Table 4 presents a summary of the action of selected function and control keys the program uses in the various control screens The function keys which are active are shown at the bottom of each screen 35 FWDCAL Version 2 Program Manual February 1992 Table 4 Function key summary lt F10 gt Continue the lt F10 gt key is used to continue the program once all entries have been made in Control Screen 2 ESCAPE returns
93. ndicated these results are suspect A repeat PRINT calibration is required after conditioning with 50 drops at height 3 PRINT Extra care should be taken to properly seat the geophones and hold the stand PRINT vertically with moderate downward pressure If deflections for the last 10 drops PRINT If vary by more than 1 mil 25 4 microns repeat the calibration at a PRINT Location If this message appears in subsequent tests contact your supervising PRINT engineer for further instructions CASE NNN PRINT Results indicate that no gain adjustments are needed CASE NYN PRINT Sensor is statistically significant at the 5X Level but gain adjustments are PRINT not indicated Test results should be carefully reviewed If anything appears PRINT suspect repeat the calibration Otherwise these results are acceptable CASE NNY PRINT Gains do not needed to be adjusted but stand position is statistically PRINT significant at the 5X Level This may be caused by failure to keep the stand PRINT vertical or improper seating of the geophones In the future care should be PRINT taken to ensure that the geophone bases are clean and well seated and the B 18 FWDCAL2 BAS March 28 1992 19 PRINT stand is kept vertical with moderate downward pressure CASE NYY PRINT Sensor and stand position are statistically significant at the 5X level but PRINT gain adjustments are not indicated Revie
94. njunction with reference calibration the procedure is repeated two times If the two sets of calibration factors agree within 0 003 for each deflection sensor then the results of the two tests shall be averaged If they are outside the limit then a third relative calibration shall be performed If the standard deviation of the three results based on n 1 degrees of freedom is less than 0 003 then the three results shall be averaged If the standard deviation exceeds 0 003 the relative calibration procedure should be repeated An example of the calculations following this procedure is shown in Appendix C The average final calibration factors should be computed and the factor for each deflection sensor should be entered into the FWD computer software e g the FWD Field Program When relative calibration is done alone typically on a monthly basis then adjustment of the calibration factors in the FWD Field Program should be made only when those changes are both significant and verified to be necessary The following guidelines are to be used to evaluate the need for adjustment to the calibration factors 1 Computed sensor adjustment ratios R between 0 997 and 1 003 inclusive are considered to be equivalent to a ratio of 1 000 In other words the required adjustments are trivial and need not be made 2 Where the adjustment ratios for one or more sensors fall outside of the range 0 997 to 1 003 the calibration process should be re
95. not significant If the standard error any of the coefficients is too large eg not significant repeat the regression using a fourth degree polynomial of the form A V A V A V Again evaluate the polynomial according to the criteria in 1 and 2 above When the evaluation criteria are satisfied and all of the coefficients are significant usually this will hoppen with either a fourth degree polynomial or a third degree polynomial record the regression coefficients ENTER THE REGRESSION COEFFICIENTS IN FWDREFCL The regression coefficients should be entered in the data acquisition program FWDREFCL Instructions for doing this can be found in the Load Cell Setup section of FWDREFCL User s Guide Any of the unused higher order terms should have their coefficients entered as 0 0 30 SHRP FWD CALIBRATION PROTOCOL April 1993 When the regression coefficients are entered in FWDREFCL the unbalanced zero the and B calibration factors the load cell signal conditioner gain factor and the date of calibration should also be entered 3l FWDCAL Version 2 Program Manual February 1992 Appendix B FWDCAL 2 0 Program Listing FWDCAL2 BAS March 28 1992 Page 1 DECLARE SUB GainAdjustMsg DECLARE SUB ReplaceSensor DECLARE SUB LatinPage1 DECLARE SUB GainsPage1 DECLARE SUB FileToScreen DECLARE SUB AvgGainToFile DECLARE SUB AvgGainToScreen DECLARE
96. ns invalidates the load cell calibration test results Excessive noise messages for drop heights 2 3 or 4 For the low drop height e g the 6000 pound load level there is seldom enough free fall time for the vibration caused by the release of the mass to attenuate before the mass strikes the plate Thus excess noise messages at the low drop height may in general be disregarded The noise due either to electrical noise or mechanical vibrations is of concern only if it results in an erroneous zero value or an erroneous peak reading The time history graphs provided by the FWDREFCL software should be viewed to determine if the noise is of concern before rejecting the calibration Standard deviations for the five readings at any drop height that differ by more than a factor of three between the reference system data set and the FWD data set Standard error of the adjustment factor see Reference Calibration Data Analysis in excess of 0 0020 Failure to satisfy the repeatability criteria for multiple calibration tests Should any of these conditions occur the load cell calibration test procedure must be repeated after identifying the source of the problem and correcting it FWD Deflection Sensor Calibration Procedure Initialize the computer data acquisition program This would include entry of the operator names FWD serial number FWD deflection sensor serial number and its current calibration factor Clean the spring loa
97. nt This can result in set and or position being statistically significant Failure to properly set the geophones in the center of holders in the stand Cleaning the base of the geophones or greater care in setting them in the stand are two remedial approaches Switching the position of the electrical connections or channels of the geophones on the FWD without making the change in the FWD computer operating program For example is sensor 7 is plugged into the channel 6 connection In this case the operating program will not use the correct gain and analogue to digital conversion factors for the specific geophone This is the reason why geophones can not be used on other FWDs without a modification to the operating computer software from Dynatest The position of the geophone connections on the FWD should be compared against the positions shown in the operating computer program Frayed cracked or worn sensor wires and loose sensor connections can be a source of inconsistent results Care should be taken not to remove a geophone from its holder by pulling on the lead wire since this can damage the connection 37 FWDCAL Version 2 Program Manual February 1992 Technical Assistance If further technical assistance is required in the use of this program please contact Cheryl Richter at FHWA LTPP Division 703 285 2183 or Nichols Consulting Engineers Reno Nevada 702 329 4955 38 Appendix SHRP FWD Calibration Protoc
98. ntigrade Stn Request OFF ON Test Checks NONE Decreasing defls Roll Off RollOFF Decr Reject prompt OFF ON Stationing Doesn t matter Temp Request OFF ON Cond Request OFF ON Variation Load NOT Checked Deflections NOT Checked Diameter of Plate 11 8 Deflector distances Doesn t matter Keep what you have 1 2 1 2 3 4 5 6 7 8 9 10 Drop No 123P4P5P6P7P8P9P0P 1P2P3PAP5P6P7PBP9POP 1P2P3PAP5P P S Heights CCCP1P1P1P1P1P1P2P2P2P2P2P2P3P3P3P3P3P3PAP4P4PA4PA4PA4P11111111111 Test PLOTS 4 Rae Save Peaks k k k x k k Ux UK Uk Uk kr Low Load His Whole His Load another TEST SETUP Store the CURRENT TEST SETUP Figure 1 Reference Calibration Test Setup for the Dynatest FWD acquisition system are registering the correct date and time If either is set incorrectly correct it before proceeding Equipment As described in Appendix A FWD Load Cell Calibration Procedure 1 If the reference load cell has not been calibrated within the last 12 months then it should be recalibrated in accordance with the procedure given in Appendix D 2 Initialize the computer data acquisition program This will include entry of operator names FWD serial number FWD load cell serial number and its current calibration factor 3 Position the FWD so that the load
99. ock on top of the load cell with the cemented rubber pad down i e in contact with the top surface of the load cell Carefully align the edges of the load cell and the two bearing blocks and center the system under the upper loading block of the universal testing machine Set the testing machine on a range equal to or slightly larger than 20 000 pounds Apply a nominal load of 20 000 pounds to the reference load cell three times Apply the load at a rate in the range of 5 000 to 20 000 pounds per minute Temporarily remove the upper wood aluminum bearing block Set the Auto Balance 28 10 1 12 SHRP FWD CALIBRATION PROTOCOL April 1993 switch on the 2310 signal conditioner to OFF Read and record the unbalanced zero voltage If this voltage 1 in excess of 5 volts the load cell has been damaged by yielding and it should be returned to the manufacturer for repair Push down the Auto Balance switch on the signal conditioner to the RESET position and release it to the ON position Adjust the Trim knob until the MetraByte board reads 0 bits Replace and align the upper bearing block rubber pad down Verify that the three guide fingers do not come in contact with the upper bearing block Apply a load of 20 000 pounds and while it is held relatively constant verify that the MetraByte board reads within 30 bits of 2000 bits If necessary adjust the Gain knob on the 2310 signal conditioner in 0 1 increments for
100. oderate level of downward pressure If deflections for the last 10 drops vary by more than 1 mil 25 4 microns repeat the calibration at a new location Gain adjustments are indicated is required to confirm the need for adjustments The gain ratios and the statistical results indicate that gain adjustments are needed A repeat calibration is required to confirm the need for gain adjustments FWDCAL Version 2 Program Manual February 1992 Table 3 Messages when a gain ratio is outside of the tolerance range Contd Gain adjustments are indicated Stand position is statistically significant at the 5 level A repeat calibration is required to confirm the need for gain adjustments Care should be taken to ensure that the g ophone bases are clean firmly seated and that the stand is held vertically with moderate downward pressure Gain adjustments are indicated Sensor and Stand position are statistically significant at the 590 level A repeat calibration is required to confirm the need for gain adjustments Care should be taken to ensure that geophone bases are clean firmly seated and that the stand is held vertically with moderate downward pressure 23 FWDCAL Version 2 Program Manual February 1992 Deflection Input Data An echo listing of the deflection and load data read as input is provided to assure the user that the information was correctly read This information is included only in the
101. of data files for this path y Def i ction Data File 4 APP PPPEPIP PEPE PEEL EPPL PDP LEAP PL EP PEP PEP ES PAPE PSP a a Fi8 Continue t Home End F7 Quit Figure 7 File selection control screen 28 fa FWDCAL Version 2 Program Manual February 1992 Control Screen 2 FWD Data File Selection The FWD File Selection screen is used to select the file to be analyzed This screen is shown in Figure 7 This can be done by entering all of the information in the entry fields 1 and 2 or using field 2 to obtain a listing of the files in the directory indicated in field 1 Field 1 Field 2 Field 3 Directory path for data file the path to the desired FWD data files may be entered in this field by typing the full drive and path name assumes default drive if no drive is specified or by pressing Enter for the current directory Nothing will be displayed in this field if the default current directory is used The path does not require a backslash as the last character If an error is detected when attempting to change to an invalid or nonexistent directory an error message will appear on the screen Show a list of files a yes no question that allows the user to select the file to be analyzed from the list of data files in the specified directory If the response is Y es then the user is placed in the directory list window and arrow keys a
102. ol SHRP FWD CALIBRATION PROTOCOL April 1993 INTRODUCTION This document describes the procedure for calibration of falling weight deflectometers FWD which was originally developed by the Strategic Highway Research Program SHRP This protocol is now administered by the Long Term Pavement Performance LTPP Division in the Federal Highway Administration The procedure is written primarily for use with the Dynatest falling weight deflectometer however it can also be used with the KUAB FWD Due to differences in the design of the KUAB certain details are not applicable Special procedures for the calibration of KUAB FWDs are included in Appendix B It may be possible to use the procedure for other types of FWDs with minor modifications of the hardware and of the data acquisition software The procedure is not applicable to the calibration of cyclic loading and other types of pavement deflection testing equipment In this procedure the deflection and load transducers from the FWD are first calibrated individually against independently calibrated reference devices This is called reference calibration and it is performed at a LTPP Regional Calibration Center or any other properly equipped location The calibration of the FWD deflection sensors is further refined by comparing them to each other in a process referred to as relative calibration Relative calibration is done as a final step that accompanies reference calibration and it can also
103. older it may not be possible to achieve the specified deflection of 16 mils at 16 000 pounds The deflection should be as large as possible To achieve the specified load levels the manufacturer recommends using Load Mode 3 9 9 small buffers 2 stack weights Adjust the drop height endswitches as necessary to be within the load tolerances In general the KUAB will be tested with the 17 millisecond rubber buffers installed The reference data acquisition system and the FWDREFCL software allow for calibration using the 25 millisecond buffers but the movement of the aluminum beam should be checked carefully to assure that there is no motion before the ground deflection peaked out The FWDREFCL software contains an number of special features to accommodate the KUAB and thus in initializing the software the FWD type should be set for KUAB The deflection sensor that is mounted through the load plate i e the center sensor 15 called sensor number zero on the KUAB and it is in position number 0 as far as FWDREFCL is concerned KUAB FWDs with version 4 0 software are able to pause during the drop sequence prior to releasing the mass This is achieved by entering the letter P after the drop height position 21 SHRP FWD CALIBRATION PROTOCOL April 1993 code during programming of the drop sequence For example the required reference calibration drop sequence would be entered as follows drop height number of drops 333 1P 6 2P 6 3
104. on Sensor and drop set are statistically significant at the 5 level but gain adjustments are not indicated Review the data carefully If anything appears suspect repeat the calibration after conditioning the FWD buffers with 50 drops from height 3 If the deflections from the last 10 drops vary by more than 1 mil 25 4 microns repeat the calibration at a new location Set and stand position are statistically significant at the 5 level but gain adjustments are not indicated Examine the data carefully If anything appears suspect repeat the calibration after conditioning the FWD buffers with 50 drops from height 3 When doing the calibration extra care should be taken to properly seat the geophones and hold the stand vertically with moderate downward pressure If deflections for the last 10 drops vary by more than 1 mil 25 4 microns repeat the calibration at a new location Set sensor and stand position are statistically significant at the 5 level Although gain changes are not indicated these results are suspect repeat calibration is required after conditioning with 50 drops at height 3 Extra care should be taken to properly seat the geophones and hold the stand vertically with moderate downward pressure If deflections for the last 10 drops vary by more than 1 mil 25 4 microns repeat the calibration at a new location If this message appears in subsequent tests contact your supervising engineer for furth
105. operating condition prior to performing reference calibration Particular attention should be paid to cleaning the magnetic deflection sensor bases to insure that they seat properly Also verify that the FWD load plate is firmly attached to the load cell In the event that the load plate is loose the lower bolts should be tightened to a torque of 7 5 lbf ft and set with Locktite before proceeding Note This torque requirement 15 applicable to the Dynatest FWDs For non Dynatest FWDs consult the manufacturer All electrical connectors should be inspected and if necessary cleaned and firmly seated The FWD should be at room temperature If the FWD has been outdoors at a very low or a very high temperature sufficient time should be allowed for it to equilibrate to room temperature It is recommended that a series of warm up drops be performed immediately prior to beginning calibration to assure that the rubber buffers have been thoroughly warmed Set the FWD mass and drop heights to produce loads within 10 percent of 6 9 12 and 16 kips 27 40 53 and 71 kN For the Dynatest FWD it is possible to be within this tolerance for the highest load and yet to have the drop height set too high Before placing the reference load cell under the load plate and with the mass positioned at drop height four the highest position verify that there is at least a four inch clearance between the highest point on the mass subassembly and the underside
106. output file and is not accessible while running the FWDCAL program An example listing of the deflection input data is shown in Figure 4 Summary Statistics An example of the summary statistics output is shown in Figure 5 This information is only included in the output file and is not accessible while running the program 24 FWDCAL Version 2 Program Manual February 1992 Program Operation The FWDCAL is an interactive program which queries the user for the required information The user program control interface consists of the following screens Control Screen 1 Select Analysis Type Control Screen 2 FWD Data File Selection Control Screen 3 Select Geophone Replaced Control Screen 4 Display Results on Screen The following three output screens are produced which display the results of the analysis and user messages Output Screen 1 Gains Table Output Screen 2 ANOVA Table Output Screen 3 Gain Change Instructions Output Screen 4 Average New Gain Factors These screens plus instructions on program installation and starting are discussed in the following sections Program Installation and Starting The program is self contained in the file FWDCAL2 EXE The program is not copy protected The basic hardware requirement is an IBM Personal Computer or IBM Compatible computer with at least 384 kilobytes K of available memory and minimum of 360K disk drive capacity A hard disk and 640K of memory are recomme
107. ove during the test period The presence of any of the following conditions invalidates the calibration data Movement of the calibration beam as measured by the deflection sensor resting on the top of the beam prior to or simultaneous with the peak deflection reading from the device under test It is entirely possible that there will ultimately be some movement of the beam as the deflection wave passes under the concrete inertial block The important criterion is whether the beam moved prior to the time that the deflection sensor on the ground registered its peak reading Beam movement can be determined by inspection of the FWD time history data files At the moment when the sensor being calibrated shows its peak reading the sensor on the reference beam should show no more than 0 08 mils 2 microns of displacement SHRP FWD CALIBRATION PROTOCOL April 1993 Excessive noise messages for drop heights 2 3 or 4 For the low drop height eg the 6000 pound load level there is seldom enough free fall time for the vibration caused by the release of the mass to attenuate before the mass strikes the plate Thus excess noise messages at the low drop height may in general be disregarded The noise due either to electrical noise or mechanical vibrations is of concern only if it results in an erroneous zero value or an erroneous peak reading The time history graphs provided by the FWDREFCL software should be viewed to determine if th
108. ow the computing formulas for the sum of squares using the following notation Sum of all deflections for sensor i Sum of all deflections for position J Sum of all deflections for drop set k T Sum of all deflection measurements The computational formulas for the sum of squares can be written as follows NumSens NumSets NumReps 900 SST 52 wr RI gt gt gt NumPos x NumSets x NumReps NumPos 55 2 NumSets M 554 NumSets x NumReps NumPos x NumSets x NumReps FWDCAL Version 2 Program Manual February 1992 WM i NumSens x NumReps B NumPos x NumSets x NumReps SSE SST SSp 554 555 9 The mean square error estimates are computed as follows SSp 52 9p 10 Position NumPos 1 EN 11 NumSets 1 a TEE 12 NumSens 1 2 SSE 13 NumReps x NumPos x NumSets 3 NumPos 2 The computed F values are 2 2 y _ SPositien 55 S sensor 14 2 Position lt 2 Sensor For the SHRP relative calibration test each main effect being tested has 6 degrees of freedom and the error term has 226 degrees of freedom The critical F statistic at the 5 confidence level is 2 14 The computed F values are compared to the critical F statistic If a computed F values is less than the critical F statistic then the corresponding hypothesis is accepted and the effect is judged not
109. peated If both sets of data agree within 0 003 the gains should be adjusted for all sensors 3 The final calibration factor is calculated by multiplying the current calibration factor for a given sensor i by its adjustment ratio R According to the recommendations of the FWD manufacturers a final calibration factor Jess than 0 98 or greater than 1 02 is possibly indicative of a damaged sensor which should be repaired by the manufacturer or replaced Final calibration factors that are within this range should be entered into the FWD data collection software 4 If any calibration factors are changed the relative calibration process must be repeated to verify the accuracy of the final values The resulting adjustment ratios should be within the range 0 997 to 1 003 for all sensors If they are not the test procedure should be repeated 16 SHRP FWD CALIBRATION PROTOCOL April 1993 Reports The full FWD calibration report shall consist of the following e Printouts of the following Dynatest FWD Field Program screens or equivalent for non Dynatest FWDs e Transducer Setup and Calibration Factors Voltages Load Cell Calibration Each of the above printouts is to be annotated with the FWD unit identification e g manufacturer s serial number or agency ID and the calibration date printouts from the FWDREFCL software The final printouts from the FWDCAL2 software for all relative calibration trials Th
110. place geophone analysis and R for Reference relative calibration 7 the last character the data file name extension for example it would be the 1 in the file name 59092289 The program writes the output files to the same directory as the FWD data files specified in Control Screen 1 This file can be printed external from the program using the DOS PRINT command or by importing it into a text editor or word processing program and then printing The following information read from the input data file header block is printed on every page FWD Serial Number Data of Calibration Data File Name Operator Name Data Set 4 of 4 This indicates the data set number when multiple data blocks are included in a file with only one header block For a single data set in the file Data Set 1 of 1 will be displayed 12 e FWDCAL Version 2 Program Manual February 1992 SHRP FWD Relative Calibration Gains Table FWD SN 8002 061 Calibration Date 05 31 91 Data File Name 61053191 RC3 Data Set 1 of 1 Operator RICK SMITH Sensor Existing Means New Out of Limit Sensor S N Gain Factor Ratio Relative Gain Tolerance 2 Range 1 840 0 986 1 0011 0 987 NO NO 2 838 0 990 0 9961 0 986 YES NO 3 833 0 989 1 0015 0 990 NO NO amp 834 0 990 1 0030 0 993 YES NO 5 835 0 993 1 0018 0 995 NO NO 6 3013 0 994 0 9980 0 992 NO NO 7 837 0 993 0 9985 0 992 NO NO Warning At least one sensor is outside the tolerance limit Verify these resul
111. pose of this procedure is to provide a tool for evaluating the validity of the relative calibration test and as an aid in interpreting its results The results of the ANOVA indicate only statistical significance relative to the amount of unexplained variation present in the data set By themselves the ANOVA results do not necessarily indicate the need for a sensor gain change that 2 test was not valid or that a repeat test is needed The ANOVA results must be evaluated relative to the information provided in the gains table and the summary statistics Statistical significance in the ANOVA results do not necessarily imply engineering significance In the Latin 54 ANOVA of the relative calibration test F statistics are computed for each main effect position set and sensor The computed F values are compared to the critical statistic 2 14 corresponds to the 5 confidence level If a computed F values is less than the critical F statistic then the the effect is judged not to be statistically significant If the computed F value is greater than the critical F statistic then the effect is indicated as being statistically significant and instructional messages are displayed in the output These messages are based the results of both the gains table and the ANOVA These messages are discussed in the program output portion of this document The details of the Latin Square experiment design layout and computations are presented in Appendix C
112. rade 18 SHRP FWD CALIBRATION PROTOCOL April 1993 fines To achieve adequate deflections the subgrade modulus should be less than 12 000 psi 80 MPa with bedrock deeper than 25 30 feet Where bedrock exists at depths of 15 to 25 feet a subgrade modulus of 7 500 psi 50 Mpa or less will be needed Test pads located where bedrock is less than 15 feet deep are likely to be very sensitive to minor variations in subgrade moisture and hence are not advisable II Equipment concrete inertial block 4 000 Ibs e 5 foot aluminum reference beam Air Cel low frequency rubber isolation pads for support of the concrete block LVDT mounting hardware deflection sensor holder assembly e magnetic tip for LVDT e Schaevitz Model GCD 121 125 0 125 inch stroke DC LVDT with Cannon connector Schaevitz metric calibrator C 41M e Measurements Group Inc Vishay Model 2310 signal conditioner with factory modification for 15 VDC and 15 VDC excitation e Keithley MetraByte Model DAS 16G A D data acquisition board with STA 16 screw terminal board and C 1800 ribbon cable The G2 version of the data acquisition board is recommended for PC XT and PC AT computers and compatibles the G1 version is acceptable Model uDAS 16G board should be used with PS 2 microchannel bus computers connecting cables Vishay to LVDT and Vishay to MetraByte e FWD reference calibration software FWDREFCL and documentation
113. re used to highlight a file in the list that can be selected by pressing Enter lt Return on some keyboards lt PgUp gt and lt PgDn gt can also be used to move backwards or forwards one page at a time where such a quantity of files exists lt Esc gt allows the user to exit the file list without selecting a file Data file name If a file was selected from the list of files in the directory specified in field 1 its name will appear in this field If the field is blank enter the file name If the file does not exist an error message will appear on the screen Once the data file has been specified use the lt F10 gt key to continue program operation The up and down arrow keys be used to change between the entry fields The lt Home gt key can be used to jump to the first entry field and the End key to the last field The F7 key be used to terminate the program 29 FWDCAL Version 2 Program Manual February 1992 Control Screen 3 Select Geophone Replaced This screen is displayed only if the replace geophone analysis is selected This screen displays the list of geophone serial numbers read from the header block in the data file The up and down arrow keys are used to highlight the replaced geophone The selection is made by pressing the Enter key The user is also given the option of exiting the program or indicating that geophone was replaced The Home and End keys be used
114. rop 5 drops at height 2 with a pause after each drop 5 drops at height 3 with a pause after each drop 5 drops at height 4 with a pause after each drop except the last Stop after the last drop plate remains down As shown in Figure 1 it is useful to program six drops at each height rather than five so that one can be cor 3 dered a spare in case drop is missed by the reference system instrumentation If t 19 five drops are successfully recorded then the data for the sixth drop can be discarded The plate should not be raised at any time during the sequence Data from both the FWD load cell and the reference system should be recorded for all drops except the three seating drops 6 Perform the load cell reference calibration twice If the two calibration factors agree within 0 003 then the results of the two tests shall be averaged If they are outside this limit then a third calibration of the load cell shall be performed If the standard deviation of the three results is less than 0 003 based on n 1 degrees of freedom then the three results shall be averaged the standard deviation exceeds 0 003 then all three calibration factors shall be discarded and the load cell calibration procedure should be repeated SHRP FWD CALIBRATION PROTOCOL April 1993 7 Upon completion of the calibration testing raise the FWD load plate and remove the reference load cell The presence of any one or more of the following conditio
115. s during the test Review the data carefully If anything PRINT appears suspect repeat the calibration after conditioning the FWD buffers with PRINT 50 drops from height 3 If the deflections from the last 10 drops vary by more PRINT than 1 mil 25 4 microns repeat the calibration at a new location CASE YYN PRINT Sensor and drop set are statistically significant at the 5X Level PRINT gain adjustments are not indicated Review the data carefully If anything PRINT appears suspect repeat the calibration after conditioning the FWD buffers with PRINT 50 drops from height 3 the deflections from the last 10 drops vary by more PRINT than 1 mil 25 4 microns repeat the calibration at a new location CASE YNY PRINT Set and stand position are statistically significant at the 5 Level but PRINT gain adjustments are not indicated Examine the data carefully If anything PRINT appears suspect repeat the calibration after conditioning the FWD buffers with PRINT 50 drops from height 3 When doing the calibration extra care should be taken to PRINT properly seat the geophones and hold the stand vertically with moderate downward PRINT pressure If deflections for the last 10 drops vary by more than 1 mil PRINT 25 4 microns repeat the calibration at a new location CASE YYY PRINT Set sensor and stand position are statistically significant at the 5 level PRINT Although gain changes are not i
116. s required to confirm the need for gain PRINT 42 adjustments When doing the calibration extra care should be taken to seat PRINT 42 the geophones properly and hold the stand vertically with a moderate level PRINT 42 of downward pressure If deflections for the last 10 drops vary by more than PRINT 42 1 mit 25 4 microns repeat the calibration at a new location CASE YYY PRINT 2 Gain adjustments are indicated and set sensor and stand position are PRINT 2 statistically significant at the 5X level A repeat calibration is required PRINT 42 after conditioning the FWD buffers with 50 drops at height 3 for adjustments PRINT 2 When doing the calibration extra care should be taken to properly seat the PRINT 2 geophones and hold the stand vertically with a moderate level of downward PRINT 42 pressure If deflections for the last 10 drops vary by more than 1 PRINT 42 mil 25 4 microns repeat the calibration at a new location CASE NNN PRINT 2 Nothing is significant Gain adjustments are indicated A repeat calibration PRINT 2 is required to confirm the need for adjustments CASE PRINT 42 Both the ratios and the statistical results indicate the gain adjustments PRINT 42 are needed A repeat calibration is required to confirm the need for gain PRINT 42 adjustments CASE PRINT 42 Gain adjustments are indicated and stand position 15 statistically PRIN
117. sducer Setup and Gain Printout Configuration File Configuration File Configuration File Transducer Setup and Gain Printout Transducer Setup and Gain Printout Configuration File Configuration File FWDREFCL Software FWDREFCL Software FWD Computer Calibration Data Acquisition System FWD Computer Calibration Data Acquisition System FWDREFCL Software Relative Calibration Data Files FWDCAL2 Software Final Gain Worksheet For SHRP FWDs Source may be different for FWDs from other manufacturers Reference calibration configuration file FWDREFCL CNF SHRP FWD CALIBRATION PROTOCOL April 1993 under the reference load cell 4 Attach the cable from the signal conditioner data acquisition system to the reference load cell Position the reference load cell beneath the FWD load plate making sure that the three guides are aligned around the plate Zero the signal conditioner with the load plate high so that there is no external load on the reference load cell Note For accurate results it is critically important that the reference load cell be zeroed with the FWD load plate in the raised position Also the signal conditioner excitation and gain must be set exactly to the levels at which the reference load cell was calibrated 5 Complete the following sequence of drops as shown in Figure 1 for a single test 3 seating drops at height 3 data not recorded followed by a pause 5 drops at height 1 with a pause after each d
118. sults Provides guidance to the user on needed gain changes further testing needs The following new capabilities have been added to the FWDCAL Version 2 0 program Computes the gains factor for a replacement sensor Processes up to three data sets in the same file Computes the average new relative gain factor from relative calibration tests performed as a part of the SHRP Reference calibration procedure three data sets must be in the same file e Processes data sets produced by Version 10 and Version 20 of the Dynatest FWD operating system software Ability to process multiple data sets in separate files without exiting the program The program displays the results on the screen and writes them to an output file for subsequent printing FWDCAL Version 2 Program Manual February 1992 Background The LTPP program uses the Dynatest Model 8000 Falling Weight Deflectometer FWD to measure the deflection response of the test pavement structures The FWDCAL computer program was developed to automate the analysis of the results of the relative calibration performed with this device Relative calibration is a technique used to verify and adjust the response of each of the deflection sensors geophones on a Dynatest FWDs so that equivalent measurements are obtained when the sensors are subjected to the same displacement direct result of this procedure is the determination of a set of multipliers necessary to k
119. sults Summary statistics mean standard deviation and coefficient of variation of the deflection response of all sensors for all drops e mean standard deviation and coefficient of variation of each sensor for all drops mean standard deviation and coefficient of variation of all sensors by position in the stand mean deflection of each sensor and average of for all sensors for each drop set mean load for each drop set mean standard deviation and coefficient of variation of the load for all drops Cochran homogeneity variance test This statistical test is used to determine if the variance of each deflection sensor s response across all drops is equivalent The standard LTPP relative calibration procedure is presented in Appendix A FWDCAL Version 2 Program Manual February 1992 Program Description The FWDCAL Version 2 0 program contains three analysis options 1 Standard Analysis 2 Replace Geophone Analysis 3 Reference Relative Calibration The Standard Analysis is designed for use in interpreting the results when a relative calibration is performed as a stand alone procedure such as for routine checks e g monthly The Replace Geophone Analysis is used when one of the geophones is replaced without an immediate Reference calibration In the Replace Geophone Analysis the response of the replacement geophone is not included in the computation of the overall average mean response of all geophones The
120. t least one sensor is outside the tolerance limit PRINT Verify these results with an additional test END IF Jnum2 gt 0 THEN PRINT Warning At least one sensor is outside the 2 range limit PRINT Notify Supervising Engineer after verifying with additional tests END IF IF Jnum1X gt 0 THEN PRINT RESULTS INDICATE THAT THE SENSOR GAINS SHOULD BE RESET END IF IF RepSens gt 0 THEN PRINT 15 PRINT repm2 USING NewGain SC RepSens END IF END SUB 12 FWDCAL2 BAS March 28 1992 13 SUB GetFileName FPath file Ext STATIC STATIC ZP WindowType 1 CLS IF ZP THEN ZP N WFile file IF Ext lt gt THEN WFile WFile Ext END IF CALL ScreenBorder CALL TitleColor Title FWD Data File Selection TLX LEN Title Col 80 TLX 2 1 LOCATE 2 ColX PRINT Title CALL NormalColor LOCATE 7 7 PRINT Directory path for data file LOCATE 10 7 PRINT Do you want a list of data files for this path Y N LOCATE 13 7 PRINT Deflection Data File Name CALL HiliteColor LOCATE 7 37 PRINT FPath LOCATE 10 60 PRINT ZP LOCATE 13 34 PRINT MFile CALL NormalColor LOCATE 25 4 PRINT F10 Continue CHR 24 CHR 25 PRINT Home End F7 Quit Item 1 Maxi tem 3 SELECT CASE Item CASE 1 OldPath FPath CALL GetString 7 37 32 FPath L 0 0 ExitCodeX FPath LTRIMS RTRIMSC UCASES FPath C
121. tand and repeating the testing a data set is obtained which can be analyzed to 1 determine an appropriate multiplier for each sensor so that all will provide identical data and 2 statistically partition the measurement errors in the data to the major sources of error as a check on the acceptability of the calibration data The FWDCAL software documented in this report was developed to perform these analyses Vil FWDCAL Version 2 Program Manual February 1992 Purpose The purpose of this document is to explain the background and use of the revised FWD relative calibration analysis computer program FWDCAL Version 2 0 developed for the Strategic Highway Research Program SHRP for use by the Long Term Pavement Performance LTPP Regional Coordination Offices RCO FWDCAL Version 2 0 program automates the analysis of the results of the relative calibration test procedure performed on the Falling Weight Deflectometer FWD geophones The program performs the following functions Checks FWD relative calibration data for compliance with the LTPP test setup requirements Calculates new relative factors for each geophone Checks the ratios between the existing and new relative gain factors to determine if they are within the established tolerances Performs an analysis of variance on the data to determine the statistical significance of key test factors Provides a statistical summary of the test re
122. the user to field 2 in Control Screen 2 from the file list without selecting a file It is also used to exit from lt PgDn gt lt PgUp gt the output screens PAGE DOWN or PAGE UP used in the directory window if more than 20 files are present to move from one page of the list to the next previous page or in output screens to move from the Gains Table to from the ANOVA Table ARROW KEYS these keys allow the user to move from one field to another on the data entry screens as well as to move from file to file in the directory window When more than one page of files are available in the directory window pressing lt 4 gt on the last row of the window places the cursor on the first row of the next page of the list Pressing lt f gt when the top line of a second or subsequent pages will move the cursor to the bottom line of the previous page in the list HOME or END these keys allow the user to quickly move to the first or last field within the data entry screen menu as well as the first or last file in the current page of the directory lt Home gt lt End gt window lt Space Bar gt SPACE BAR the lt Space Bar gt key is used to exit the various warnings or errors that appear at the bottom of the data entry screen lt CR gt lt Enter gt CARRIAGE RETURN or ENTER used to accept a data input lt lt gt value once it has been entered or selected QUIT used to exit the program in
123. ts with additional tests RESULTS INDICATE THAT THE SENSOR GAINS SHOULD BE RESET SHRP FWD Relative Calibration Gain adjustments Results of this test indicate the possible need to adjust the gains This should be confirmed with a repeat test Gain adjustment should be performed when the New Gain Factors for two independent calibrations are within 0 002 of each other Gain adjustments should be made ONLY to the out of range geophone s After adjusting any gain setting the relative calibration test must be repeated to confirm that all sensors are within tolerance Figure 2 Example print of output file for the Gains Table 13 FWDCAL Version 2 Program Manual February 1992 SHRP FWD Relative Calibration Latin Square ANOVA Table FWD SN 8002 061 Calibration Date 05 31 91 Data File Name 61053191 RC3 Data Set 1 of 1 Operator RICK SMITH Variation Sum of Degrees of Computed Critical Source Squares Freedom Position 9 40E 02 1 57E 02 Set 1 96E 00 3 26E 01 Sensor 4 34E 01 7 23E 02 Error 8 29E400 3 67E 02 TOTAL 1 08 01 Gain adjustments indicated and drop set is statistically significant at the 5 level Set significance may be due to warming of the buffers or consolidation of pavement materials during the test A repeat calibration after conditioning the FWD buffers with 50 drops from height 3 is required to confirm the need for gain adjustments If the deflections from the last 10 drops vary by more t
124. um of Degrees of Mean Computed Critical PRINT Source Squares Freedom Square f f PRINT c9 07929922 4 4 Data HH Hat HHHH Ht HH IF FLPos gt 1000 OR FLSet gt 1000 OR FLSens gt 1000 THEN Data 2 HH HH END IF PRINT USING Data Position CSNG SSLPos DegFreelPosX CSNG MSLPos CSNG FLPos CritFLPos PRINT USING Data Set CSNG SSLSet DegFreeLSet CSNG MSLSet CSNG FLSet CritFLset PRINT USING Data Sensor CSNG SSLSens DegFreelSensX CSNG MSLSens CSNG FLSens CritFLSens PRINT USING Data Error CSNG SSLE DegFreeLEX CSNG MSLE PRINT USING Data TOTAL CSNG SSLT DegFreeLT PRINT Jnum1 gt 0 THEN SELECT CASE LSAM CASE YNN PRINT Gain adjustments are indicated and drop set is statistically significant at PRINT the 5X level Set significance may be due to warming of the buffers or PRINT consolidation of pavement materials during the test A repeat calibration PRINT after conditioning the FWD buffers with 50 drops from height 3 is required PRINT to confirm the need for gain adjustments If the deflections from the last 10 PRINT drops vary by more than 1 mil 25 4 microns repeat the calibration at a PRINT new location CASE YYN PRINT Gain adjustments are indicated Sensor and drop set are statistically PRINT significant
125. urrDrive CHR GetDriveX GetDir CCurrDrive CurrPath CurrDrive CurrDir IF FPath THEN IF MID FPath 2 1 THEN ChkDrive LEFT FPath 1 IF GoodDriveX ChkDrive THEN check if valid drive REDIM PUText 1 PUText 1 Drive ChkDrive is not a valid choice Please try another path CALL PopupError ExitCode 0 FPath OldPath ELSE drive OK check dir IF RIGHT FPath 1 X THEN FPath LEFT FPath LEN FPath 1 END IF RIGHT FPath 1 THEN FPath FPath END IF CALL CDir FPath ErrFlag IF NOT ErrFlag THEN path OK CALL CDir CurrPath ErrFlag switch back to curr dir ELSE path not OK REDIM PUText 2 PUText 1 Error occurred switching to FPath PUText 2 May not be valid path Please try again CALL PopupError ExitCode 0 FPath OldPath END IF END IF ELSE drive letter in specified path IF RIGHT FPath 1 X THEN FPath LEFTS FPath LEN FPath 1 END IF 13 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 515 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 53C 55 53 533 534 535 536 FWDCAL2 BAS March 28 1992 14 CALL CDir FPath
126. w calibration results carefully PRINT If anything appears suspect repeat the calibration taking care to ensure PRINT that geophone bases are clean and properly seated and the stand is kept PRINT vertical with moderate downward pressure CASE ELSE END SELECT END IF V Vee ede fede fe e e de dee dede dede Cochran test results ese de dede de e ede dede defende e dee defe de IF ProblemExist 1 THEN PRINT Cochran test variance between geophones indicates variance for Sensor No BigDef PRINT is significantly larger than the other sensors Please consult the output file END IF END SUB B 19 769 770 771 775 776 778 780 781 782 785 786 787 788 789 790 791 792 793 794 795 796 797 798 800 801 802 803 804 805 806 807 808 809 810 811 812 815 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 850 831 852 833 834 835 836 FWOCAL2 BAS March 28 1992 Page 20 SUB LatinSqDesign 8 ee de fe e de dede dee de ee de dee dee de dee dede Subprogram for Latin Square Design analysis 8 Ve de dee de de e e fe fe fe de de dede de eee de dede dee e de DIM Tj 7 Tk 7 Tij 7 7 Tik 7 7 7 1 7 7 7 DIM SSumTi 7 SSumTj 7 SSumTk 7 SetSum 7 TotalLoad 35 Ini t i al 1 Vari ables to Zero
127. w the data carefully If anything PRINT 2 is suspect repeat the calibration after conditioning the FWD buffers with 50 PRINT 42 drops from height 3 If the deflections from the last 10 drops vary by more PRINT 42 than 1 mil 25 4 microns repeat the calibration at a new location CASE YNY 24 FWDCAL2 BAS March 28 1992 25 PRINT 42 Set and stand position are statistically significant at the 5 Level but gain PRINT 42 adjustments are not indicated Examine the data carefully If anything appears PRINT 42 suspect repeat the calibration after conditioning the FWD buffers with 50 PRINT 42 drops from height 3 When doing the calibration extra care should be taken to PRINT 42 properly seat the geophones and hold the stand vertically with a moderate PRINT 2 Level of pressure If deflections for the last 10 drops vary by more than 1 PRINT 42 1 mil 25 4 microns repeat the calibration at a new location CASE YYY PRINT 42 Set sensor and stand position are statistically significant at the 5 level PRINT 2 Although gain changes are not indicated these results are suspect repeat PRINT 2 calibration is required after conditioning with 50 drops at height 3 When PRINT 42 doing the calibration extra care should be taken to properly seat the n PRINT 2 geophones and hold the stand vertically with a moderate level of pressure PRINT 2 If deflections for the last
128. ystem deflection sensor holder Run the magnetic base over a piece of fine grained emery paper that is placed on a firm flat surface such as the upper flange of the aluminum beam to assure that it 1s clean SHRP FWD CALIBRATION PROTOCOL April 1993 8 Place one deflection sensor in the sensor holder and position the LVDT holder so that the LVDT and the FWD sensor are aligned 9 Place a second deflection sensor on top of the LVDT holder so that it will measure the movement of the end of the beam and hence of the LVDT housing 10 Complete the following sequence of drops as shown in Figure 1 for a single test 3 seating drops at height 3 data not recorded followed by a pause 5 drops at height 1 with a pause after each drop 5 drops at height 2 with a pause after each drop 5 drops at height 3 with a pause after each drop 5 drops at height 4 with a pause after each drop except the last Stop after the last drop plate remains down As shown in Figure 1 it is useful to program six drops at each height rather than five so that one can be considered a spare in case a drop is missed by the reference system instrumentation If the first five drops are successfully recorded then the data for the sixth drop can be discarded The plate should not be raised at any time after the seating drops One complete FWD time history plot should be studied for the fifth drop at each drop height to verify that the calibration beam does not m

Download Pdf Manuals

Related Search

Related Contents

CNC 8035 - Manual de Operação  SPEEDLINK SL-8691-SBK-01 microphone  æµ¢à¾  25 manual del usuario para la encuesta sobre inversión de  Sistema FIMPES Autoestudio UVM 2008 GUÍA DEL USUARIO  取扱説明書  MultiBlender™  The WadBOS ecosystem model as an example for building  取扱説明書 - 株式会社リッチェル ライフケア用品  User interface for electronic devices  

Copyright © All rights reserved. Failed to retrieve file