Manual Check Using STAADPRO - sefindia.org

1 1 Manual CHECKING OF STAADPROINPUTSAND OUTPUT Consulting Structural Engineer, Coimbatore, :It is well known fact that users of any software for structural analysis and Design do notknow whether the program is having any bugs or its correctness while Using . Since anyprogram developed may contain some error or bugs it is necessary for the userstocheck the model and analysis and design resultsat some point to Check the resultsmanually so as to make sure input data while modeling the structures is assumed and the input loads on the structure arein par withthe actualcondition of the support condition considered are as per site countercheckto verify that H=0; V=0 and M= users shouldbe knowing the universal wellspread phrase of the word GOINGOOUT.

2 An attempt has been made to listthe number of Manual checks that can be carried outwhile Using STAADPRO and as an aid the following Check list are list of checks may be applicable not only to STAADPRO but alsoto any softwareused for structural analysis and :It is important to Check the UNITS at every stage while modeling since it may lead to aunexpected error in the output. While modeling use oflength unitsmay be inmeter forbeam, column and plate and while entering the properties it isusualpractice to makeuse of either mms or inch unit since we know the dimensions which are inputtingthe LOADSon memberscheck the UNIT system is in KN and metersystem since the program continues to use the previous unit till it is inputting the LOADS to the structure facility is available in STAADPRO as perthe screen Multiple times by mistake the user would have without his knowledge created toomany members and structure.

3 Better use this toolmenu to remove the multiple2structures. It is the responsibility of the applicator to verify that there exists onlyone structure and not more than it for any model.** Check forsolids with Negative Volume(Jacobian) Check for Warped Solids.**2. Check Duplicate is naturaland human nature to make mistake and error while entering datawhilecreatingthe model by means of Nodes, Members (Beam and column) and plates inSTAADPRO. To take care before continuingandto alleviatecumulating more errorsit is goodpracticeto Check whether there is any duplicate nodes, members andplates which would have slipped in the model while creating the model by means ofthe tool available as shown in the screen Check Orphan Nodes:Sometimes by mistake some nodes would have been added and no members areformed through thenodes and they wouldhave been left as an orphan.

4 It isnecessary to Check and remove these orphan nodes to proceed for Warped plates:If the model is created by means of plates it is good to Check whether the platesformed contain any warpusing thecommand Check for Warped plates afterselecting the Improperly connected plates and Check Beam Plate connectivity:The above two commands in STAADPRO enable the user to Check the continuity ofthe plate withother plates and beams formed while modeling the structure. If they arenot well welded then the distribution of forces and continuitybetween them cannot beguaranteed. Hence these checks Check Beam plate connectivity Check is important in the case of Wall andplatemodeling.

5 Vie sec of the Staad manualfor more from the above available toolfor checking the model the followingmanualcalculations of certainsimple itemswill be of use to Check the input dataandcorrectness of the model before proceeding to analysis and :Correct assessment of loads both dead and live loads are important sinceexcessive assumed loads may lead to uneconomical member sizes and excessive loads will be adding more weight in the case of order to have equilibrium . V=0 under the Load case DEAD LOAD calculatethe total dead load on all floor slabs andcheck it against the output by TO Check : Using a single support for the whole structure RUN the ANALYSISand find out thetotalsupport reaction in Y axis FYfrom the outputof the program.

6 Checkwhether the above two values are in agreement tothe manually calculatedvalues. If the resultsvary then there is some error or mistaketook place whileenteringthe same procedure can be carried out for the LIVE LOADfor both FLOOR LIVELOAD and ROOF LIVE the single support is not considered or modeled then use all the supports andcopy the values of Fy to EXCEL and get the sum of the FYand Check whether ittallies with the manually LOAD:Itis possible to generate the wind load by the program provided it is defined atthe start by adding the required input data. Inorder to Check the valuesgenerated by the program a simple Manual Check can be made as find the point load FX or FZ at a jointas nodal wind forcecalculate thetributary area for the corresponding node and multiply it with the intensity :Area = (h1+h2)/2*(L1+L2)/2* intensity of note that the consistence unit shall be and h2 are the height above and below the joint in meters and L1 andL2 are the width of the bay on either side of the nodein meter units.

7 If h1 = h2= , L1= and L2= then the tributary area for the node is=(4+3)/2*(5+6)/2 = an intensity of 1 the nodal force shall be = KN. This can beverified with the values generated by CONDITIONS:Usually while modeling a structure either FIXED or HINGED support condition isproposed. If the support condition is FIXED the there shall ,FY,FZ, Mx,My and MzFor HINGED there shall be no order to account for the soil spring the modulus of subgrade reaction Ks has to beconsidered for the support Check AGAINST STAAD RESULTS FOR SEISMIC FORCES**For the verification of the values generated by the STAADPRO program an example istaken up to illustrate. The input is alsogiven in the appendixso that the STAADPRO user can copy and run it to know how it is framemodeled is checked easily forthe followingitems:The structureis 36x21m and is symmetrical in x and Z direction as well as in verticalelevation and its total height from the footingis 74m.

8 (21 storey)The building is in Zone III and the time period as per IS 1893-2002(PartI) for infill analysis through STAADPRO the followingscheck is carried out to verify andcheck the resultsbetween manualcalculationandthe software TIME PERIOD:As per IS CODE 1893-2002(Part I)T = dwhere d is the directionalong the EQ = 36 = = 21 = output of STAADPRO isTIME PERIOD FOR X 1893 LOADING = SECTIME PERIOD FOR Z 1893 LOADING = SEC**Happy to note from the above comparison that the program is doing fine upto checkThe Dead load as per Staad for 19 floorsa.)slab including self weight ofcolumns, beams, brick wall weightandshear wall as per dimensionsthat were provided by the the program under the load case 1 the following loads are weight (columns,beams and shear walls for the entirebuilding) the exteriorbeams except on shear wall only are dead load on slab-Self weight of slab+Finish+Construction load +15% forfurniture, staircase, water tank etc is added with an intensity of 6 Manual Check forthese items are carried out load: Area of floor x no.

9 Of floors x intensity of load=36x21x6x20 = the input is arranged for this in STAADPRO we get the same valueascalculated manuallyfrom the output.** load:Total lengthof beamin one floor =2x{( )+( )}= per floor = = due to brickwall alround exterior beams =19x1080= due to Parapet mheight of wall=2x{36+21} dead load due to brickwall =20520+ = WEIGHT = = Default density valueof ^3 is taken from STAAD for all floors = {(36x4+21x9)}x20 =. beam = {30x2+36x2+15x2+21x7)= = KNTotal of a+b+c = + + + + + per STAAD output as furnished below total load = output is:**STATIC LOAD/REACTION/EQUILIBRIUM SUMMARY FOR CASE NO. 1 LOADTYPE DEAD TITLE LOAD CASE 1 DEAD LOADTOTAL APPLIED LOAD ( KNMETE ) SUMMARY (LOADING 1 )SUMMATION FORCE-X = FORCE-Y = FORCE-Z = percentage of difference =( )*100 = ** LOAD Check :Live load for floor is 3 (office )and roof Live load as as per IS 875as access is thereis taken.}

10 **STATIC LOAD/REACTION/EQUILIBRIUM SUMMARY FOR CASE NO. 2 LOADTYPE LIVE TITLE LOAD CASE 2 FLOOR LIVE LOADTOTAL APPLIED LOAD ( KN METE ) SUMMARY (LOADING 2 )7 SUMMATION FORCE-X = FORCE-Y = FORCE-Z = above is the result from per Manual calculation is 36x21x19x3 = which exactly LOAD/REACTION/EQUILIBRIUM SUMMARY FOR CASE NO. 3 LOADTYPEROOF LIVETITLE LOAD CASE 3 ROOF LIVE LOADTOTAL APPLIED LOAD ( KN METE ) SUMMARY (LOADING 3 )SUMMATION FORCE-X = FORCE-Y = FORCE-Z = per calculation = which is the same as per Check THE VALUE OF SA/G_____Ah =ZISa/(2*R*g) for the value of Tx and TZ for mediumsoil the value ofSa/g for Tx from code = = = Tz = = per Staad Sa/g for x direction and for Z direction are in agreement with manualcalculation.