Structural Engineering Software - Modern Steel Construction
Contents
1. entire structure as a whole You simply rotate the structure to the right face say N S and apply the load with the mouse Loads and load combi nations are saved and together with the saved geome try the problem is solved Solution After the analysis is done the pro gram puts the user in the Results window In there one can print or display graphics of deflected shapes force diagrams etc The user can also see results in a tabu lated form Figure 1 3 is an example of detailed results for a beam You can look at the results for the structure as a whole from different angles or the results of individual members This is useful to share with other engineers or to display overall results for clients Steel Design Figure 1 4 shows one way to display results of the LRFD code check by stress ratios Deflection and drift limits can be specified to design members The only thing I could not figure out from the user s manual is what ver sion of the AISC LRFD specification was being used Dynamic Analysis Linear dynam ic analysis is available I did not use it in this review but I can only imag ine it is as simple as the other mod ules As a whole I liked this software a lot In the geometry definition you can display and print floor plans with dimensions and shapes which is very useful for quick reviews The user s manual needs more informa tion but the online help is very com prehensive a2. J g E ih Pe lo RS J ee i A ale Preeportlies t JH plm ct nerais HOE La ae ee ee ame Bese Fr br T ar FF a Flee Preperlics Be Paper ries uml Fri FT p rira Figure 2 1 ETABS data file EE Er ETERA PEPERELET F AEMT L i Figure 2 2 ETABS graphical 3D view Figure 2 3 ETABS PLOTTER module e STEELER this program is a code check for steel The version of ETABS I was able to look at is known as the standard version as opposed to the more advanced ETABS Plus The limita tions of the Standard version com pared to the Plus version are the size of the problem one can solve limited to 6000 equations and non linear time history analysis is not available in the standard version Yes just like STRAP the user needs the dreaded key a mechani cal plug that must be inserted in your computer s parallel port in order for the software to be run to run ETABS however on the up side the user s manual is in a book for mat not a huge binder I can actual ly put it on my shelves with my other computer books Input The input file is a data file that can be generated using a text editor Figure 2 1 is an example of a data file displayed using the Modern Steel Construction January 1997 Notepad application for Windows Like any data file it must follow strict rules including the traditional commas spaces periods etc ETAB SIN is a program designed not to rep
3. Frames are limit ed to eight loads three gravity three lateral and two dynamic However as many load combina tions as needed can be examined using those eight basic loads Load combinations do not have to be lin ear Output PLOTTER and READER are two DOS programs that run within Windows Figure 2 3 is a deflected shape displayed using PLOTTER The only member forces available in PLOTTER are the ones using the eight available loads so if I want to see the effects of 1 4D I can t However using READER which is also a DOS based program it is possible to look at combinations for every element or joint READER does not allow any edits you can dis play any results you want in tabular form Steel Design ETABS uses the lat est LRFD Specification Unfortunately STEELER requires its own input file so after running ETABS you have to go in and check or create a STEELER input file using a text editor To check stress ratios resulting from STEELER PLOTTER can be used Figure 2 4 shows a screen from TIMER This particular plot shows the variation of the bending moment about the major axis at the bottom of column three on the fourth level versus time It is also possible to display structural energy dissipation accel eration records and other variables versus time for a better understand ing of member behavior under cyclic loads In general using this series of programs requires learning several programs because of the
4. STRUCTURAL ANALYSIS RIAA Gi REvIEWS OF SIX PROGRAMS By Jacques Cattan Jacques Cattan is a Senior Staff Engineer Structures at the American Institute of Steel Construction Inc Much of his job involves working on preliminary design studies for out side fabricators engineers and archi tects VERY JANUARY MODERN STEEL Hy consrecerioy PUBLISHES A COMPREHENSIVE LIST OF STRUC TURAL ENGINEERING SOFTWARE avail able on the market I always look forward to it hoping to spot the new tool that will make my work a little quicker and a little easier Why First every year personal com puters get faster and have more fea tures As a structural engineer I want to use this technology to my and my employer s benefit A lot of industries are benefiting from the so called computer revolution and I am on the look out for the great design software that will bring our profession the latest easiest and most efficient computer technology Second part of my work at AISC is to do building design studies and for some reason they are always due yesterday Therefore I am always looking and hoping for new software that might be useful After reading so many software manuals though I have an urge to put in my own disclaimer so here we go the opinions I express in this article are only mine and in no way do they represent AISC or Modern Steel Construction Also to put things into perspective I am not a software speciali
5. ckling analysis of elements eigenvalue problem and the capability of generating wind loads for lattice towers The Recapitulation module is the equivalent of the READER program in ETABS The user can look at the input file and results in a tabular form In the Graphical analysis module the user can generate save and plot various graphics files such as moment diagrams and structural displacements The Steel Design module is excellent non only do you get a code check per the ASD and the LRFD AISC specifications but ROBOT V6 will suggest an alterna tive section that I could use if I wanted to modify the model I got code check and design which is rare Finally I did not try the connections design module but I saw that it was possible to output data to create a Design Advisor input file I hope this program will be developed for Windows 95 because it is a good tool Due to review time V3 5 was used in this review Please note that V4 0 has now been released For more information on the new release see page 18 of this issue RESEARCH ENGINEERS STAAD III RELEASE 22W Operating System Windows Organization STAAD III The STAAD III environment is well integrated for a windows appli cation despite the fact that it con sists of several programs e STAAD PRE graphical input generation program e STAAD III analysis and design program e STAAD POST graphical output STAAD III is a very powerful pro gram Like STRAP
6. hat follows are my impressions when I used each software for a cou ple of my designs Some graphics are from my designs while some are from examples provided with the software itself For more information on STRAP please circle number 28 on the read er service card in the back of the magazine for WinSTRUDL circle 27 for ETABS circle 31 for Robot V6 circle 51 for RISA 3D circle 40 and for STAAD III circle 34 ATIR ENGINEERING SOFTWARE DEVELOPMENT LTD STRAP VERSION 7 0 Operating system Windows Organization This graphical pro gram is organized around seven pull down menus e Files to manage various models e Geometry to graphically input models e Loads to define applied loads and examine load combinations Solve to run the analysis Results to examine results either graphically or using text e Design to run the steel code checker e Dynamics to run and examine a dynamic analysis Model Input The Files menu has an option to import a DXF file and convert it to a STRAP input file I found this fea ture very useful In this electronic age I often can get a DXF file why recreate one in the form of an input file for STRAP when I can simply con vert it Also in that same menu one can convert a STRAP file into a DXF file The default steel tables default colors units and materials can be setup here The graphical input of the model was excellent and very natural to me as a Windows u
7. ification to check the section I had or to let STRUDL design or select a section for me This is a very useful feature because it is not just code checking but actual section design or selec tion However the LRFD Specification used is from 1984 not the current 1993 Specification Editing WinTools are unique to STRUDL This is a set of tools which guide you to make modifica tions to your model You fill out boxes on one screen and copy the contents into the file Basically you do not have to start from zero rather the instructions are given to the user and all you do is input the variables required Figure 3 5 A Figure 3 5 C A S T modification tools shows the tool to modify member releases the user fills in the mem ber number or numbers to be modi fied and what the releases are In general the online help is good and useful The user s manual can be developed further I liked the ease of input for data the speed of execution of the analysis Like all these building analysis programs I wish they had a module for code loads such as wind live load reduc tion or even snow loads With today s computer power there no reason why not Overall it is a very good program and well integrated METROSOFT ROBOT V6 VERSION 3 5 Operating System DOS Only Organization Tree like structure of several programs e Design 3D module graphic input editor e Analysis module Recapitulation module input and ou
8. ight of the bat one is NO KEY to run it It is worth buying just for that almost Second under organization I had a hard time summing up how RISA 3D is set up not because it is badly done but rather because it is concise and truly within one command cen ter Figure 6 1 shows the central window for RISA 3D The display is made of a series of powerful spread sheet that the user can call on from the menu Figure 6 1 shows the Coordinates spreadsheet I found the spreadsheet terminology used by RISA 3D to be very appropriate because as you look at different screens such as Figure 6 1 you get the copying cutting and group selection features of a powerful spread sheet granted in DOS environ ment but it works The menu selections and the spreadsheet layouts are easy to use and very intuitive The biggest draw back is of course the fact that you have to define nodes and elements in a non graphical way but since the program is interactive the graphical output helps the user The term interactive is defined by RISA Figure 6 1 RISA 3D coordinates spreadsheet Modern Steel Construction January 1997 y Erlin Aorenta Ae Figure 6 2 RISA 3D graphical output showing moment diagrams Technologies as the data you are working on to define the problem is instantly available to all parts of the program For that reason you can define a few nodes and elements say a floor level look at the graphical
9. ions from all three model building codes My software would include a steel tips module by AISC that would help me optimize my preliminary design and of course it would all come on a CD Finally if I were a DOS die hard I might have gone with RISA 3D Good Luck For more information on STRAP please circle number 28 on the read er service card in the back of the magazine for WinSTRUDL circle 27 for ETABS circle 31 for Robot V6 circle 51 for RISA 3D circle 40 and for STAAD III circle 34 Modern Steel Construction January 1997
10. it has an eight node plate element as well as the traditional beam element for build ing analysis The eight node ele ment allows for plate analysis and stress distribution It is difficult to have several figures of this program because it is so well integrated in windows Unlike STRUDL where each program has a different screen or ETABS where some programs are DOS based some are Windows based STAAD is all windows Figure 5 1 shows a typical window including results from a sample analysis run Input STAAD 3D is still based on a text input file The user can write the text input file using a built in text editor STAAD III is so well integrated that if you prefer using STAAD PRE like me you can at the same time check the text version simulta neously STAAD PRE is not very intuitive since the user is graphically developing a text input file it is a good ETABSIN The multiple windows and the grid display are very useful fea tures as seen in Figure 5 1 After running STAAD III to obtain analysis results the mul tiple windows capacities to dis play displace ments member forces and steel design checks Figure 5 2 is a typical output of the steel design checker The design capabili ties as opposed to code checking are rather disap pointing RISA TECHNOLOGIES RISA 3D VERSION 2 1 Operating System DOS program that runs under Windows Organization Central DOS screen Two compliments r
11. lace the input file but rather to help the user generate an input file ETABSIN runs in Windows the idea is to define a grid place column lines on the grid and connect columns to form bays Then using a series of spreadsheets combined with the mouse the user assigns elements and properties to column lines and bay lines Figure 2 2 shows the graphical Assign 3D view with the assignment tool set on columns Also open in Figure 2 2 is the 3D view orientation window and the Zoom and Pan window After gener ating the input file using ETABSIN I had to go back and actually check the text file The graphical interface was cumbersome and it felt awk ward as if it was designed more to create the text version input file rather than to make my task easier Figure 2 4 ETABS TIMER module I end it up using the text file to wrap up things Analysis ETABS is a very compre hensive analysis program It includes lateral load generation from all major codes seismic loads as well as wind loads I found this feature very useful ETABS is capable of P Delta dynamic analysis as well as non linear time history analysis using the plus version of the pro gram ETABS views the structure as a series of frames If you look at the structure as stacked floors it is very difficult to use ETABS You must have your entire structure clearly defined before starting to input frames as opposed to stacking up floors and then attempting to optimize frames
12. lack of inte gration between pre processors ETABSIN analysis ETABS and post processors PLOTTER STEEL ER etc The best thing about ETABS is that for advanced projects it gives you the power of SAP90 specifically for buildings C A S T WiNSTRUDL Operating System Windows Organization Wmaster is the cen tral location for all programs around WinSTRUDL e File to run a single input file e Project allows to manage several files from one project e WinFrame graphical frame Beam continuous beam analysis LRFD Steel design and code check Winkdit text editor Plot plotting program WinTool WinEdit fill in tool input Figure 3 1 shows Wmaster the nerve center of STRUDL In Figure 3 1 I included two fea tures Project and File When you ask for a File you get a specific run that was previously saved It is presented in a dialog box as shown in Figure 3 1 here Job Demol you can launch WinTool Plot etc This file is part of a Figure 3 1 C A S T WMaster Project that you PRaaRSSis cele tesinduue Ba create the advantage ofa project collection is that you can create new files by copying part or all of old files Then each file represents an analysis run Input Figure 3 2 shows two windows of Win Frame which is the graphical input interface When a new File is created the user has a series of dialog boxes EEMI helping in the 5 creation of the first fra
13. ly make any required changes and then add some more RISA 3D is not a graphical program but has the powerful database features that form the back bone of graphical pro RISA 3D E oS grams The analysis is very efficient Once the user has defined the model geometry and loads one can request the model to be solved for a particu lar load combination Figure 6 2 is a graphical output showing moment diagrams for a specified load combi nation In addition to beam and col umn analysis one can also analyze plates using RISA 3D RGI initi iari Figure 6 3 RISA 3D loading and force diagrams which can be selected for particular members The steel design features are very useful you can ask the program to compute K factors and you can inter actively redesign members after stress checks are done Loading and force diagrams can be selected for particular members and printed out as shown in Figure 6 3 Here I selected one of the bottom columns and one can see a concise and com plete description of the element CONCLUSIONS My perfect structural analysis and design software would have the model input power of STRAP the analytical power and steel design capabilities of ROBOT V6 the inte gration and post processing capabili ties of STAAD III the lateral load generation capabilities of ETABS and the detailed output of WinSTRUDL My perfect software would include load generation capa bilities including live load reduct
14. me and its grids defaults for member proper ties joints etc Once the user finishes all the required infor mation he she is presented with the X Y window peal es P 9RLCE Ege ab JA II a Illi shown in Figure o em 3 2 At this fame point the main su thm seers frame can be modified graphi cally using the pull down menu or tools located on the left side of the screen Once set the frame can be copied to form a 3D structure and a 3D view window can be opened It is very easy to add loads joints or restraints by specify n akad Pet HAT Shea Lam rir OEE AIRFIF JL PI I OEF E F LF FOF E d in mE T FT Figure 3 3 C A S T text editor ing specific views such as the roof or the moment frame ete Basically you define everything for the model here Analysis Now that we have a file we can run it as shown in Figure 3 1 using the Run button When I ran Modern Steel Construction January 1997 Figure 3 4 C A S T post design the 3D five story building it was fast because I was using a Pentium processor and Windows 95 WinSTRUDL is truly designed for fast 32 bit execution Steel Design After I finished the analysis I was able to view tabulated results using the View Result button of Figure 3 1 Figure 3 3 is an exam ple of how the text editor displays input files or results To design spe cific elements I used the Post Design button as shown in Figure 3 4 I can use the LRFD Spec
15. nd very accessible Too bad STRAP does not include auto matic building codes load genera tions and live load reductions COMPUTERS amp STRUCTURES NC ETABS VERSION 6 0 Operating System DOS but runs under windows ETABSIN is a win dows program Organization This software is organized around six independent programs e ETABSIN this is a pre processor program that helps the user pre pare an input file for ETABS Like any pre processor it is not necessary to create an input file It is however helpful to have ETABSIN e ETABS this is the actual struc tural analysis program The user has to prepare a text input file and run the analysis After ETABS runs a series of output files are created for use with the output programs e PLOTTER this program allows the user to see and print the structure geometry deflected shapes and force diagrams one can also export DXF files e READER this program allows the user to look at text files they cannot be changed using READ ER so to change your input file you need to use a word processor or text editor such as notepad in windows e TIMER this program displays variables along a timeline such as load displacement curves or earthquake records Modern Steel Construction January 1997 DEP PIEN ETUE SMP gt Rig oe ea cee Lateral Lewd feels aang Eip dete yrum YXTINs WAFAT ENNA Wek G f EEH i M enem omen Ebi A Heidal Pata PIMI IPAE E PEED
16. ser Figure 1 1 shows three windows displayed as I was assigning braces to a bay I often get plans of individual floors using STRAP it was very simple to stack floors as I saw them on paper As I did that in one window I saw my isometric view display my struc ture as a whole in another window assuring I am not just leaving a col umn hanging Assigning boundary conditions element properties and floor diaphragms by a click ofa mouse was very good almost as easy as using a word processor Figure 1 1 STRAP Graphical Inout Model J a Pii LE EE a oe ihid JERHT i Figure 1 2 STRAP applied load eee bee TAa hn SHEN porer bli ere Wee ce A ee TS ee SH Pee muy ee TI ee ee ee lint Atacand ie FF PLE 1 ir bfi Am 64 LF 1d LES ELLY PO a eT E Ta M Hyas Figure 1 4 STRAP LRFD results display That is exactly what I am looking for from a computer based analysis soft ware package easy input I can do the structural engineering while the computer does the number crunch ing Sure there is the risk of clicking on the wrong point but in a text based program watch out for those commas L o a d Definition A click of the mouse got me to the Loads menu where I can very naturally apply loads on joints beams or floors This is also where I defined load combina tions Users can specify moving loads checkered patterns and ask for a P Delta analysis Figure 1 2 shows a load applied to the
17. st or programmer I did not evaluate the software for its accuracy but rather its ease of use The design studies I do at AISC can vary from a simple single story warehouse to a 26 story high rise I need to come up with a structural concept do the analysis and present my results Sounds simple I need easy input accurate analysis and comprehensive presentable paper and electronic output I don t have a draftsman The following list includes the software packages I examined and the version number I thank each of the producers for providing me with their products for this review Modern Steel Construction January 1997 e ATIR Engineering Software Development Ltd STRAP v7 0 e C A S T WinSTRUDL e Computers amp Structures Inc ETABS v6 0 e Robobat Robot V6 v3 0 e RISA Technologies RISA 3D v2 1 e Research Engineers STAAD III v22W You might notice that several packages are missing For many I am guilty as charged I only have so much time to review software and this magazine only has a limited number of pages to present reviews in the future we will look at some more packages In other cases how ever I am not guilty for example Ram Analysis refused me permis sion to evaluate RamSteel If there is a particular software package you would like me to look at in the future please feel free to reach me at AISC via snail mail phone 312 670 5430 fax 312 670 5403 or e mail cattan aiscmail com W
18. tput tabular screens e Graphical Analysis module input and output graphical display e Steel Design module Call me spoiled but it was very difficult to work in this DOS only program ROBOT V6 does not run under Windows at all so the user has to exit Windows to run the pro gram Now having said that as far as analytical features are concerned this is the most powerful software of the six I looked at The Design 3D module is the graphic input editor which creates an ASCII input file that the user analysis using the Analysis module It is a typical DOS graphical envi Modern Steel Construction January 1997 ronment in other words you to click and open several windows before getting to the result This input graphics file can do everything Windows based programs can The user can select members rotate the model or specify joints and loads Despite its DOS feel Design 3D has some powerful features such as gen erating nodes for members by drag ging a member using a mouse As you can see it is very Windows like with the limitations of DOS The user can generate code based wind loads snow loads as well as seismic loads for the UBC 1991 code Once the model is defined the Analysis module can be called to solve the structural analysis ROBOT V6 is capable of linear elas tic analysis P Delta analysis large displacements non linear analysis and time history analysis Two unique features I found in ROBOT V6 are the linear bu
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