LF10 USER'S MANUAL - CISC-ICCA
Contents
1. LF10 USER S MANUAL Lateral Forces 2010 icca CISC LF10 User s Manual User s Manual Lateral Forces 2010 First Edition September 2011 Copyright O 2011 All rights reserved This manual or any part thereof must not be reproduced in any form without the written permission of the publisher ISBN 978 0 88811 150 0 Canadian Institute of Steel Construction 3760 14 Avenue Suite 200 Markham Ontario L3R 3T7 Tel 905 946 0864 Email info cisc icca ca Website www cisc icca ca PREFACE PREFACE Prepared by the Canadian Institute of Steel Construction CISC the Lateral Forces 2010 LF10 Excel spreadsheets for Wind and Seismic Loads replace the Lateral Forces 90 LF90 program of the CISC Steel Design Series for the IBM Personal Computer and compatibles The Microsoft Excel spreadsheets are part of a continuing effort by the Canadian structural steel industry to simplify the design of steel structures Accordingly LF10 joins the Handbook of Steel Construction and other design aids made available to designers by the Canadian Institute of Steel Construction LF10 is based on the requirements of the National Building Code of Canada 2010 the Supplement to the National Building Code of Canada 2010 and CSA S16 09 Design of Steel Structures The user must understand the design requirements of these documents before attempting to use the LF10 spreadsheets In addition to explaining how to use the spreadsheets this manu2. ccocoocccncnonoccnocanoncnononananononanos 13 Reset BUT OM Are eee aaa ak 13 Projectintormatio Merine E E aauseeeasneess 13 Level heights and dimensions INput rnrrrnranrverrannnnvnnrnrnnrrnnsennnnenssnennvnnnsennrrensnsnnensssennne 13 Site importance category and terrain INPUt oooccccnnoncccnonanocanonononannnnnonnnnnnnnnonnnnnnnn nano 14 NBC climatic wind data and user specified wind pressure cccoocccncconoccnonononcnnnnnnnnnnncnnnns 14 Limit state type of procedure and Building on hill Input ccconccccnanoncccnononannnnnnnos 15 Forces and overturning on building Output eerervrrrrronnrrvrrsnnrrrnesrennrnessenrrenssnsrnnneseennn 15 CHAPTER 4 SEISMIC LOADS seriada AR A 17 Reset A O 17 A aure 17 Level Heights nd Weights Input 17 TABLE OF CONTENTS Site a a Class IPUR 18 NBC site parameters and user specified spectral accelerati0nS oooccccnnoccccnononannnnnnno 18 SFRS and Period for the X direction IpUt occnonnccccnonoccconononnncnononnnncnanonnnononononcnnnnnnnnnnnnns 19 Forces and Distribution X direction Output ccccooccnnccoooancnnnonannnonnoannnccnononnnonanonononnnnnos 20 Force Multiplier for Deflection Calculations X Direction oooocccnnnocccnnccononnncconannnononnnnos 24 Seismic Loads Calculations Y Direction iria 24 APPENDIX A TECHNICAL NOTES WIND vicctsussseserscsveste ecto ccuveadseedderonseanectssaedeansnete canvdccdeoties 25 Effective Buildin
3. 2 0 s F S 2 0 2 for T 2 4 0 s NBC site parameters and user specified spectral accelerations You may enter user specified spectral accelerations by checking the box Check to enter user specified spectral accelerations Alternatively the NBC 2010 seismic data for the CHAPTER 4 SEISMIC LOADS location may be used by unchecking the box SFRS and Period for the X direction Input Table 1 indicates the different available steel seismic force resisting systems in LF10 Seismic together with their corresponding Rg and R factors the NBC formula used for the period calculation and limits on the period for strength and deflection calculations Table 1 Seismic Force Resisting Systems Structural system Limit Limit strength deflect Ductile moment resisting frame 5 0 1 5 0 085 h 1 5 Ta 2 05 Moderately ductile moment resisting frame 3 5 1 5 0 085 h 15T 2 05 Limited ductility moment resisting frame 2 0 1 3 0 085 h 1 5 Ta 2 05s Moderately ductile concentrically braced frame 3 0 1 3 0 025 h 2 07 2 05 Tension compression braces Moderately ductile concentrically braced frame 3 0 1 3 0 025 hn 2 0T 2 0s Tension only braces Limited ductility concentrically braced frame 2 0 1 3 0 025 h 2 0T 2 0s Tension compression braces Limited ductility concentrically braced frame 2 0 1 3 0 025 h 2 0 Ta 2 05 Tension only braces Ductile buckling restrained braced frame 4 0 1 2 0 025 h 2 07 2 05 Duc
4. by following the instructions on the CISC website www cisc icaca ca Type in your Activation Key in the cell at the bottom of the window and click the ACCEPT DISCLAIMER AND ENTER button to acknowledge the software license You may save the workbook with your Activation Key to avoid having to enter it again in the future As you access the spreadsheet zoom settings for the different sheets are automatically adjusted to the window size Design Standard Design standards include the National Building Code of Canada 2010 and the Structural Commentaries Part 4 of Division B to the National Building Code of Canada 2010 Seismic force increases based on the type of SFRS and the building height are determined according to CSA S16 09 LF10 User s Manual Units The International System of Units SI is used exclusively in LF10 The required units for each item of input data is given as the data is requested In general the units and abbreviations are as follows length metres m area square metres m force kilonewtons kN area load kilopascals kPa moment kilonewton metres kN m Data Input The building geometry and design parameters are input using tables cells and drop down menus which appear on the screen Data can be typed into the tables pasted or dragged and copied from one cell to others Input cells and drop down menus are on a white background T mechanics 1 36 s Figu
5. first level is considered to be transmitted directly to the foundation This force Fo is only included in the output for the shear force corresponding to the entire building at the base for purposes of foundation design If necessary the value of Fy can be calculated by subtracting the shear for level 1 from the shear of the entire building at the base In calculating the overturning moment the point of application of the wind force on the parapet is taken at its mid height Figure 6 illustrates the tributary areas and applied wind forces for the entire building Figure 6 Tributary areas for wind forces CHAPTER 4 SEISMIC LOADS CHAPTER 4 SEISMIC LOADS The lateral earthquake design force at the base of the structure V is computed and distributed according to NBC 2010 Article 4 1 8 of the NBC 2010 The Equivalent Static Force Procedure for Structures Satisfying the Conditions of Article 4 1 8 7 is used to determine static loads LF10 Seismic will perform load calculations for the selected location and type of Seismic Force Resisting System SFRS A warning will appear if a system not allowed by the NBC is selected The user should use the CISC Steel Seismic Systems software to determine which systems are allowed for the location and building height and to verify whether S 0 2 is less than or equal to 0 12 in which case the requirements of Article 4 1 8 need not apply Reset Button Click on the Reset button to in
6. grouped as in Appendix C Thus for example North York will not be listed under Toronto but under its own name The province and location of the building are selected by means of a drop down menu The location list is updated when the province is changed When the province is changed the first location name is initially selected The spectral response acceleration values Sa T for periods T of 0 2s 0 5s 1 0s and 2 0s are the values given in Appendix C The importance category of the building is selected through a drop down menu Available choices are given in NBC Table 4 1 8 5 and the importance factors for ULS given in the table are used in the spreadsheet Note that NBC stipulates additional system restrictions to Post disaster buildings refer to Article 4 1 8 10 Site classification depending on the ground profile is based on Table 4 1 8 4 A of NBC 2010 When Site Class F is selected the used can directly input values of acceleration and velocity based coefficients F and F Refer to the NBC for more information on selecting the appropriate Site Class Acceleration and velocity based coefficients F and F are based on Tables 4 1 8 4 B and 4 1 8 4 C and are linearly interpolated for intermediate values of Sa 0 2 and S 1 0 Values of the design spectral acceleration S T are determined as follows S T F S 0 2 for T 0 2 s F S 0 5 or FaSa 0 2 whichever is smaller for T 0 5 s F Sa 1 0 for T 1 0s F S 2 0 for T
7. n Lis Wihi where W and h are the portion of W and the height at level x respectively The additional force at the top Fi is defined by F 0 07 T V Fi need not exceed 0 25V and is set equal to zero when Ta lt 0 7s The overturning moment at level x is calculated by My My 1 Ve hy hx 1 For conventional construction and other systems M is multiplied by a reduction factor J 4 1 8 11 7 1 When h lt 0 6 hn J J A p hy 0 6hy 2 For all other cases J 1 0 Force Multiplier for Deflection Calculations X Direction NBC 2010 allows the use of Ta Tmechanics for the purpose of calculating deflections Tueflections subject to the limits given in Article 4 1 8 11 3 d v and listed in Table 1 under the Limit deflections column Base shear calculations as described above for the X direction for strength Vstrength are then carried out using Taeflections in order to obtain Vaeflections The seismic force multiplier for deflections is then calculated as V eflections Vstrength Seismic Loads Calculations Y Direction On a separate sheet the user can select a different SFRS and specify a different value of Ta mechanics for the Y direction Otherwise input calculations and output are identical to that for the X direction APPENDIX A TECHNICAL NOTES WIND APPENDIX A TECHNICAL NOTES WIND As a supplemental reference the following pages describe the engineering formulas inc
8. al contains information relating to the design procedures and assumptions incorporated into the spreadsheets Thus the designer will recognize the capabilities and limitations of the spreadsheets and through the various options available interject personal design requirements or engineering judgement LF10 has been tested extensively and to the best of our knowledge all data and information contained in both the spreadsheets and this manual were correct at the time of publication The Canadian Institute of Steel Construction does not assume any responsibility for errors misinterpretations or oversights resulting from the use of the Lateral Forces 2010 spreadsheets or this manual Canadian Institute of Steel Construction LF10 User s Manual TABLE OF CONTENTS PREFACE EE EE EE NT 3 TABLE OF MENN NN 4 CHAPTER 1 PURE rek 7 CHAPTER 2 GENERAL ici ci id a ke one kne 9 Hardware and Software Requirements rrnrarannvnnneennrvvnrannnnvnsenenrnnnsennrnnnssnnnnenssnennrnsssenssensene 9 Accessing the SOFA danene 9 Destacada EE 9 UNS une 10 Data INPUt drenere catausdenavecche cdvatedenesecsue capanetaresseetueustes 10 A eee dn 10 Pr blem Si e LO Sinai 10 Geometry and Sign Conventions arista edu dae ute 10 AN 11 LIMON Sii A At 12 Spreadsheet Protect soresissiiiesssosisteniinss nenies iii a a aaa 12 Printing RePOrtsuurannsd agree aana E a a E Ea aaah 12 CHAPTER 3 WIND LOADS eeo 13 Lateral wind loads on the entire building Wind sheet
9. e direction under consideration by means of other established methods of mechanics Tmechanics Using a structural model that complies with the requirements of Sentence 4 1 8 3 8 This is done by checking box Check to input a different value Forces and Distribution X direction Output The upper limits to the period Ta as given in Article 4 1 8 11 are used to determine the fundamental period T used in load calculations Those limits are given in Table 1 under the Limit strength column The spectral acceleration S Ta is linearly interpolated from S T values The higher mode factor M and its associated base overturning moment reduction factor J are based on Table 4 1 8 11 For S T M the interpolation is carried out using the product S TJMy While any SFRS can be selected LF10 checks the NBC height restrictions according to Table 2 This verification is done using the sum of the storey heights even if a lower value of H is entered for the fundamental period calculation For Post Disaster buildings only ductile systems Ry gt 2 0 are allowed If the selected system is not allowed a warning will appear together with a box Check to continue anyway If the selected SFRS is not allowed this box must be checked in order to display the output A graph showing the modified design spectral acceleration S T M will be displayed For systems with R42 1 5 and a site class other than F the upper limit for the ba
10. e level of the building i e at the top of the hill is also provided Forces and overturning on building Output By clicking the check calculations button below the title of the section the user can display the values of Cp Ce or Ce and Cg or Cz used in wind pressure calculations Values of Ce or Ce and Cg or Cg are given for each level These coefficients are also computed at an elevation above the base equal to a quarter of the height of the first level In the next drop down menu available only if Ultimate Limit States are selected the user must indicate whether the wind loads act as a Principal Load of as a Companion Load This will affect the Load factor which is then displayed below For Serviceability Limit States the load factor is invariably 1 0 LF10 User s Manual The output of this sheet is presented in the form of a table of applied forces F shears V and overturning moments M for each direction and level For each level the output is given as illustrated on Figure 6 While the applied force is at the top of a level the overturning moment and shear given for that level are referred to its base For wind force calculations tributary areas at a given level generally include half of the level heights immediately above and below the level For the roof the tributary area includes half of the level below and the entire area of the parapet above At the base level the wind on the bottom half of the
11. g Wisin serceru isana aena ienai den 25 APPENDIX B TECHNICAL NOTES SEISMIC sssssssssssssssssssssssrsessessrrsrrsesstrstentnnsrestnsrensreseee 27 Method of Analysis NBC 41 87 2 27 SFRS General Restrictions NBC 4 1 8 9 mmmnnnnnnnnrnrnrnrnnnsnersnnnsnsnsnnnsnnnsnennnnennnnnnnennnennnennnennnnnns 27 Post Disaster Buildings NBC 4 1810 0d A Ri 27 mr LF10 User s Manual CHAPTER 1 PURPOSE CHAPTER 1 PURPOSE The CISC Lateral Forces 2010 spreadsheets LF10 have been developed to compute lateral forces due to wind and or earthquake according to the 2010 National Building Code of Canada There are two separate spreadsheets for Wind and Seismic loads Both use the same format for input and output The Wind module LF10 Wind determines wind storey forces in each direction in accordance with either the Static Procedure for High Rise or the Dynamic Procedure which are given in Commentary I of the Structural Commentaries Part 4 of Division B to the National Building Code of Canada 2010 The Speed up over hills and escarpments is implemented The Earthquake module LF10 Seismic determines seismic storey forces in accordance with the Equivalent Static Force Procedure of the NBC including Commentary J of the Structural Commentaries Part 4 of Division B to the National Building Code of Canada 2010 and CSA S16 09 Design assumptions built into the spreadsheets have been kept to a minimum When an assumption is made it is documen
12. ged after entering the level data all data previously entered for levels above the new number will be lost The inter storey height hs for each level must be a decimal value in metres between 0 1 and 99 DX is the building width at a given level for wind loading acting in the X direction and DY is the width for wind loading in the Y direction These dimensions are used in the calculation LF10 User s Manual of tributary areas They should be representative of the entire building envelope and thus include the thickness of cladding A roof parapet with a height of up to 1 5 m can be added to the roof level The parapet dimensions in the X and Y directions are the same as the dimensions of the roof level The parapet is not included in the building height for subsequent calculations Optionally dimensions at the base the total height and effective widths in both directions can be displayed Effective widths are calculated according to NBC Article 4 1 7 2 Site importance category and terrain Input LF10 Wind incorporates the climatic data from Appendix C of the NBC 2010 Both the province and the city are listed alphabetically Note that cities which are part of a metropolitan region are not grouped as in Appendix C Thus for example North York will not be listed under Toronto but under its own name The province and location of the building are selected by means of a drop down menu The location list is updated when the provi
13. gure 3 Building dimensions Wind forces act through the centre of geometry while earthquake forces act through the centre of mass at each floor level Output Output load tables are given by load type and principal building direction In every load table generated the output includes the lateral force the cumulative shear and the cumulative overturning moment at the base of each level The results of intermediate calculations are available and can be displayed by clicking the check calculations button as shown on Figure 4 ty Figure 4 Check calculations button All wind loads are factored For design purposes wind loads can be compared directly to the earthquake forces Output is given in cells with a light yellow background The level output is given as illustrated on Figure While the applied force is at the top of a level the overturning moment and shear for that level are at the base LF10 User s Manual Figure 5 Level output Limitations The spreadsheet can calculate lateral loads for buildings rectangular in plan only and with flat roofs Irregular building shapes must be approximated by a rectangular model The building length and width may change from level to level but any level rotated in the horizontal plane about the vertical axis must be approximated by a non rotated level by the design engineer The spreadsheet will not perform a structural analysis or a dynamic analysis The purpose of the s
14. is selected the user must input B the critical damping ratio for the building and natural frequencies of vibration frp and fap y for the X and Y directions respectively It is noted that the empirical formulas for period calculations used in seismic design should not be used for wind forces If desired the effects of wind speed up over hills and escarpments can be included in accordance with paragraphs 13 to 16 and 21 of Commentary and for both the Static and Dynamic Procedures The choice of hill and escarpment shape and parameters for maximum speed up is given according to Table l 1 If a hill or escarpment is selected the user must also input e Hy the height of the hill or escarpment or the difference in elevation between the crest and the terrain surrounding the hill or escarpment upwind Negative values of Hn are beyond the scope of LF10 Wind e Lu the distance upwind of the crest to where the ground elevation is half of Hn e x a horizontal distance from the crest The spreadsheet includes figures describing the hill or escarpment geometry as needed Only one amplification factor for speed up is considered for the entire building If a hill is specified the speed up will affect both the X and Y directions Also conservatively the same x distance is used for the windward and the leeward faces of the building Optionally the user can display the factors used for the calculation of C C The maximum speed up factor at the bas
15. itialize the input data Project Information The user can enter the date a project designation and fill in the prepared by box to identify projects both on the screen and on a printed report The contents of those fields are not used by the spreadsheet Level Heights and Weights Input The number of levels must be an integer from 1 to 100 This input value is used to display the appropriate number of data cells for input and output results A minimum of 8 levels of input and output are shown when a figure is used to illustrate the table Please note that if the number of levels is changed all data entered for levels above the new number of levels will be lost The inter storey height hs for each level must be a decimal value in metres between 0 1 and 99 W is the dead load or weight assigned to each level The dead load is defined in Article 4 1 4 1 The dead load assigned to each level must be a positive value For reference and verification both the sum of the inter storey heights and the total dead load are given at the bottom of the table The input values for inter storey height and weight for each level are shown on Figure 7 LF10 User s Manual Figure 7 Level height and weight input Site and Class Input LF10 Seismic incorporates the climatic data from Appendix C of the NBC 2010 Both the province and the city are listed alphabetically Note that cities which are part of a metropolitan region are not
16. le concentrically braced frame Tension MIN 1 24 IF h gt 32 1 h 32 0 03 1 compression braces Clause 27 5 2 3 Moderately ductile concentrically braced frame Tension only MIN 1 12 1F h gt 16 1 h 16 0 03 1 braces Clause 27 5 2 5 Limited ductility concentrically braced frame Tension MIN 1 24 IF h gt 48 1 h 48 0 02 1 compression braces Clause 27 6 2 1 Limited ductility concentrically braced frame Tension only MIN 1 24 IF h gt 32 1 h 32 0 03 1 braces Clause 27 6 2 3 Conventional construction Occupancies other than Assembly Moment resisting frame Clause 27 11 3 a IF lgF Sa 0 2 20 35 Conventional construction Occupancies other than Assembly MIN IF Rimi 60 1 9 1 5 Braced frame Clause 27 11 3 a IF himi IF h gt 15 1 h 15 0 02 1 1 Conventional construction Occupancies other than Assembly Shear wall Clause 27 11 3 a Where hjmit is the applicable height limit from Table 2 The maximum lateral earthquake force Vmax rdro 1 3 IS given by V 155 S Ta Mylg max RdRo 1 3 T 13 The amplified base shear is obtained as follows 1 For Conventional construction Occupancies other than Assembly Vamp MIN Vinax raro 13 V Al 2 For all other systems Vamp V A The final base shear V used in the level distribution is given by V Vamp W LF10 User s Manual The lateral seismic force at each level Fx is computed according to 4 1 8 11 6 E a V F Wxhx x
17. luded And only overall loads acting on the entire building s lateral load resisting system are computed The applicability of the Static or Dynamic Procedure is not checked by LF10 Wind See Article 4 1 7 2 and Figure 1 1 Wind forces generated by the spreadsheet are to be used for strength and deflection design of structural lateral load resisting systems they are not applicable to the design of cladding In LF10 Wind the internal pressure pi is not considered to affect loads on the building structure since the windward and leeward faces are assumed to be vertical and identical for each direction The need to consider internal pressure pi should be reviewed by the project engineer Lateral wind loads on the entire building Wind sheet This sheet performs load calculations for the entire building without consideration of torsion Partial or unbalanced load conditions are not included Reset Button Click on the Reset button to initialize the input data Project information The user can enter the date a project designation and fill the prepared by box to identify projects on the screen and on a printed report The contents of those fields are not used by the spreadsheet Level heights and dimensions Input The number of levels must be an integer from 1 to 100 This value is used to adjust the number of data cells for input and output A minimum of 8 levels is shown Please note that if the number of levels is chan
18. nce is changed When the province is changed the first location name is initially selected The Reference velocity pressure q1 50 is the one given in Appendix C The importance category of the building is selected through a drop down menu Available choices are given in NBC Table 4 1 7 1 The terrain type is also selected through a drop down menu Open terrain exposure Exposure A and Rough terrain exposure Exposure B can be selected Exposure C in the dynamic procedure of the NBC is not implemented in LF10 Wind Exposure C should be used with caution and only in the centre of large cities LF10 Wind does not permit interpolation between exposures NBC climatic wind data and user specified wind pressure The user may select a user specified pressure by checking the box located directly under the Reference velocity pressure input box Alternatively the NBC 2010 climatic wind data for the location may be used by unchecking the box CHAPTER 3 WIND LOADS Limit state type of procedure and Building on hill Input The limit state for calculating wind loads is selected through a drop down menu Ultimate limit states and Serviceability limit states are the available selections which will affect the value of the Importance factor ly according to Table 4 1 7 1 The desired procedure for wind load calculation is selected through another drop down menu No additional input is necessary for the Static Procedure If the Dynamic Procedure
19. orporated into the LF10 software For a complete nomenclature of variables please refer to the National Building Code of Canada NBC 2010 Effective Building Width Optionally dimensions at the base the total height and effective widths in both directions can be displayed The effective building width for wind loads is calculated according to Clause 4 1 7 2 as follows Y h DX DX effective Th Where h is the height above the base to level i LF10 User s Manual APPENDIX B TECHNICAL NOTES SEISMIC APPENDIX B TECHNICAL NOTES SEISMIC Particular restrictions pertaining to seismic design according to the National Building Code of Canada NBC 2010 are listed below Method of Analysis NBC 4 1 8 7 The user is responsible for determining the applicable method of analysis either the Equivalent Static Force Procedure described in Article 4 1 8 11 or the Dynamic Analysis Procedure described in 4 1 8 12 Only the former method is included in LF10 Seismic SFRS General Restrictions NBC 4 1 8 9 If the chosen SFRS violates 4 1 8 9 either because of a building height limitation or because of the value of le Fa Sa 0 2 a warning will appear in the worksheet Post Disaster Buildings NBC 4 1 8 10 The user must verify that Post disaster buildings meet the requirements of 4 1 8 10 in particular with regard to structural irregularities Table 4 1 8 6 Also a warning will be displayed if Rg lt 2
20. preadsheet is not to replace calculations performed by a design engineer but to assist the engineer in computing lateral loads It would be impractical to provide a complete step by step illustration of wind or earthquake calculations whether the design is performed manually or by means of a spreadsheet Therefore output from LF10 provides sufficient key information about each load combination so that the results can be easily verified by a qualified design engineer It is left to the design engineer to verify load calculations and judge their applicability with respect to design criteria Spreadsheet Protection The spreadsheet is protected some cells cannot be modified but can be selected for example to copy the results Printing Reports Excel printing options can be used to print reports It is recommended to adjust the position of page breaks according to the number of levels in the building CHAPTER 3 WIND LOADS CHAPTER 3 WIND LOADS LF10 Wind can calculate lateral wind loads either according to the static procedure for high rise buildings or the dynamic procedure The user is responsible for choosing the appropriate method Ultimate limit states and serviceability limit states can be considered separately The wind is assumed to act in either of the two principal building directions through the centre of geometry of the given level Only horizontal loads are computed vertical wind pressures acting on the roof are not inc
21. re 1 Input cell Error Checking During data input possible errors are checked for input data type e g words entered where a number is required or data outside the normal range When an error is found a brief description is displayed and the user is prompted to correct the input To allow maximum flexibility the permissible range of input values is wide For example when entering the period Ta mechanics a decimal value between 0 1 and 99 must be entered Other Period Q Please enter decimal value between 0 1 and 99 Cancel Figure 2 Error warning for invalid data Problem Size Limitations The LF10 spreadsheet can compute forces for buildings up to 100 levels in height Geometry and Sign Conventions The building geometry is specified in LF10 by entering the height width and length of each level Wind module only and then stacking the levels vertically The levels are numbered in ascending order starting at the bottom of the building with level number zero being ground LF10 Seismic permits buildings with SFRS located along orthogonal axes only Refer to the NBC for buildings for other SFRS orientations CHAPTER 2 GENERAL Building geometry and dimensions conventions in LF10 are shown on Figure 3 I TYPICAL LEVEL Wind Load X direction 1 I I I I I I I I I I l I l I I I LAS W I Y Building envelope reference y q pa ACIS AE AO O S E E Wind Load Y direction Fi
22. ruction Occupancies other than NL NL 60 40 40 Assembly Moment resisting frame Conventional construction Occupancies other than NL NL 60 40 40 Assembly Braced frame Conventional construction Occupancies other than NL NL 60 40 40 Assembly Shear wall Other steel SFRS not defined in Table 4 1 8 9 15 15 NP NP NP NL system is not limited in height NP system is not permitted The minimum lateral earthquake force Vmin based on the weight W is obtained from the formula in 4 1 8 11 2 V _ S Ta Mylg min RaRo LF10 User s Manual A second minimum lateral earthquake force Vmin2 for wall systems is given in 4 1 8 11 2 a y _ S 4 0 Mylg min2 RaRo and for all other systems in 4 1 8 11 2 b S 2 0 Mylg Vminz RaRo The maximum lateral earthquake force Vmax Is calculated according to 4 1 8 11 2 c _ 25 0 2 Ig max 3 RIR The base shear V as a function of the weight W is thus obtained from 1 For Ra gt 1 5 and a Site Class other than F V MIN Vingy MAX Vmin Vminz I 2 For all other systems V MAX Vmin Vmin2 An amplification factor for the base shear A based on requirements in S16 09 is then calculated Table 3 lists the systems affected by this increase and the respective formula used for calculating the amplification factor CHAPTER 4 SEISMIC LOADS Table 3 Amplification factors in 16 09 Structural system Base Shear Amplification Factor A Moderately ducti
23. se shear is displayed on the graph The red circle indicates the final acceleration used for the base shear calculation including the 16 09 amplification for height if applicable The equivalent Static Force Procedure for structures satisfying the conditions of Article 4 1 8 7 is then used to calculate the base shear CHAPTER 4 SEISMIC LOADS Table 2 Height limits used in LF10 Structural system Restrictions I F S 0 2 lgF Sa 1 0 lt 0 2 20 2to 20 35to gt 0 75 gt 0 3 lt 0 35 lt 0 75 Ductile moment resisting frame NL NL NL NL NL Moderately ductile moment resisting frame NL NL NL NL NL Limited ductility moment resisting frame NL NL 60 30 30 Moderately ductile concentrically braced frame NL NL 40 40 40 Tension compression braces Moderately ductile concentrically braced frame NL NL 20 20 20 Tension only braces Limited ductility concentrically braced frame Tension NL NL 60 60 60 compression braces Limited ductility concentrically braced frame Tension NL NL 40 40 40 only braces Ductile buckling restrained braced frame NL NL 40 40 40 Ductile eccentrically braced frame NL NL NL NL NL Ductile plate wall NL NL NL NL NL Limited ductility plate wall NL NL 60 60 60 Conventional construction Assembly occupancies NL NL 15 15 15 Moment resisting frame Conventional construction Assembly occupancies NL NL 15 15 15 Braced frame Conventional construction Assembly occupancies NL NL 15 15 15 Shear wall Conventional const
24. ted in the spreadsheets and in this manual In this way the designer has complete control over the calculations To facilitate validation and verifications where possible and relevant intermediate results are available and can be displayed as an option mr LF10 User s Manual CHAPTER 2 GENERAL 9 CHAPTER 2 GENERAL Prior to using the Lateral Forces 2010 spreadsheet it is advisable to become familiar with a brief list of the spreadsheet s capabilities features and limitations They are as follows Hardware and Software Requirements The Microsoft Excel spreadsheet requires a version of Microsoft Excel be installed The spreadsheet was optimized for use with Microsoft Excel 2007 Macros must be enabled to display more than the Welcome screen To enable macros go to Excel options gt Trust Center gt Trust Center Settings gt Macro Settings and click on Enable all macros You will then need to restart Excel for the new setting to be considered To disable the Privacy warning that might be shown by Excel go to Developer Ribbon click Macro Security click Privacy Options and uncheck all notifications Accessing the Spreadsheets When you access the LF10 spreadsheets either the Wind or Seismic module the first worksheet you will encounter is the Welcome sheet containing an Introduction and Disclaimer In order to proceed you will need to obtain your Activation Key from CISC
25. tile eccentrically braced frame 4 0 1 5 0 025 h 2 0T 2 0s Ductile plate wall 5 0 1 6 0 05 h 2 0T 4 0s Limited ductility plate wall 2 0 1 5 0 05 ihn 2 0 Ta 4 05 Conventional construction Assembly occupancies 15 1 3 0 085 hele 1 5 Ta 2 0s Moment resisting frame Conventional construction Assembly occupancies 1 5 1 3 0 025 h 2 07 2 0s Braced frame Conventional construction Assembly occupancies 1 5 1 3 0 05 h 2 0T 4 0s Shear wall Conventional construction Occupancies other than 1 5 1 3 0 085 h 1 5 Ta 2 05s Assembly Moment resisting frame Conventional construction Occupancies other than 1 5 13 0 025 h 2 07 2 05 Assembly Braced frame Conventional construction Occupancies other than 1 5 1 3 0 05 h 220 4 0s Assembly Shear wall Other steel SFRS not defined in Table 4 1 8 9 1 0 10060506 1 0T 2 05 LF10 User s Manual For the fundamental period calculation the sum of the storey heights is used by default To modify the value and enter the height above the base to level n the uppermost level in the main portion of the structure check the box Check to input a different value uncheck to use the sum of storey heights The entered value must be between 0 and the sum of the storey heights The user must specify the type of SFRS LF10 then calculates the fundamental period of the system according to NBC T ormula LF10 enables the user to enter a fundamental period in th
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