I am running a STAAD Pro CONNECT design on a 2D truss with a double-pitch top chord. While running a member optimization, I received the following message and I don't know why: "ERROR IN SELECTION PROCESS FOR MEMBER- (member #)". I have run multiple designs with single-pitch top chords using the same parameters; however, I believe it may have something to do with the double-pitch top chord. As I look through the results, one of the iterations changed the numbers of the all top chord members to -1 and changed the profile to "T". Does anyone have any idea as to why this is happening? See below for STAAD input.
STAAD TRUSSSTART JOB INFORMATION JOB NAME XXXXJOB CLIENT XXXXJOB NO XXXXJOB PART XXXXJOB COMMENT XXXXENGINEER NAME XXXXENGINEER DATE XXXXEND JOB INFORMATION INPUT WIDTH 79 UNIT INCHES KIP JOINT COORDINATES100 0 0 0;101 99 0 0;102 198 0 0;103 297 0 0;104 396 0 0;105 495 0 0;106 594 0 0;107 693 0 0;108 792 0 0;200 0 84 0;201 99 85.878 0;202 198 87.756 0;203 297 89.634 0;204 396 91.512 0;205 495 89.634 0;206 594 87.756 0;207 693 85.878 0;208 792 84 0;MEMBER INCIDENCES100 100 101;101 101 102;102 102 103;103 103 104;104 104 105;105 105 106;106 106 107;107 107 108;200 200 201;201 201 202;202 202 203;203 203 204;204 204 205;205 205 206;206 206 207;207 207 208;300 101 201;301 102 202;302 103 203;303 104 204;304 105 205;305 106 206;306 107 207;400 101 200;401 102 201;402 103 202;403 104 203;404 104 205;405 105 206;406 106 207;407 107 208;UNIT FEET KIPDEFINE MATERIAL STARTISOTROPIC STEELE 4.176e+06POISSON 0.3DENSITY 0.489024ALPHA 6.5e-06DAMP 0.03END DEFINE MATERIALMEMBER PROPERTY AMERICAN100 TO 107 TABLE ST W8X31200 TO 207 TABLE T W16X31300 TO 306 TABLE LD L40406 SP 0.0625400 TO 407 TABLE LD L40406 SP 0.0625CONSTANTSMATERIAL STEEL ALLSUPPORTS200 PINNED100 108 208 FIXED BUT FX MX MY MZ102 104 106 FIXED BUT FX FY MX MY MZ201 TO 207 FIXED BUT FX FY MX MY MZLOAD 1 LOADTYPE Dead TITLE DEAD LOADJOINT LOAD*BOTTOM CHORD101 TO 107 FY -0.297100 108 FY -0.1485*TOP CHORD201 TO 207 FY -1.848200 208 FY -0.924SELFWEIGHT Y -1MEMBER LOAD*BOTTOM CHORD100 TO 107 UNI GY -0.173*TOP CHORD200 TO 207 UNI GY -0.254LOAD 2 LOADTYPE Live TITLE LIVE LOADJOINT LOAD*BOTTOM CHORD101 TO 107 FY -0.001100 108 FY -0.001*TOP CHORD201 TO 207 FY -0.001200 208 FY -0.001MEMBER LOAD*BOTTOM CHORD100 TO 107 UNI GY -0.347*TOP CHORD200 TO 207 UNI GY -0.001LOAD 3 LOADTYPE Roof Live TITLE ROOF LIVEJOINT LOAD*BOTTOM CHORD101 TO 107 FY -0.001100 108 FY -0.001*TOP CHORD201 TO 207 FY -2.723200 208 FY -1.3615MEMBER LOAD*BOTTOM CHORD100 TO 107 UNI GY -0.001*TOP CHORD200 TO 207 UNI GY -0.001LOAD 4 LOADTYPE Snow TITLE SNOWJOINT LOAD*BOTTOM CHORD101 TO 107 FY -0.001100 108 FY -0.001*TOP CHORD201 TO 207 FY -0.001200 208 FY -0.001MEMBER LOAD*BOTTOM CHORD100 TO 107 UNI GY -0.001*TOP CHORD200 TO 207 UNI GY -0.001LOAD 5 LOADTYPE Wind TITLE WIND (+X)JOINT LOAD*BOTTOM CHORD101 TO 107 FX 0.001100 108 FY 0.001*TOP CHORD201 TO 207 FX 0.001200 208 FX 0.001LOAD 6 LOADTYPE Wind TITLE WIND (-X)JOINT LOAD*BOTTOM CHORD101 TO 107 FX -0.001100 108 FX -0.001*TOP CHORD201 TO 207 FX -0.001200 208 FX -0.001LOAD 7 LOADTYPE Wind TITLE WIND (-Y)JOINT LOAD*BOTTOM CHORD101 TO 107 FY -0.001100 108 FY -0.001*TOP CHORD201 TO 207 FY -1.089200 208 FY -0.5445MEMBER LOAD*BOTTOM CHORD100 TO 107 UNI GY -0.001*TOP CHORD200 TO 207 UNI GY -0.001LOAD 8 LOADTYPE Wind TITLE WIND (+Y)JOINT LOAD*BOTTOM CHORD101 TO 107 FY 0.001100 108 FY 0.001*TOP CHORD201 TO 207 FY 4.22200 208 FY 2.11MEMBER LOAD*BOTTOM CHORD100 TO 107 UNI GY 0.001*TOP CHORD200 TO 207 UNI GY 0.001LOAD 9 LOADTYPE Seismic-H TITLE SEISMIC (+X)JOINT LOAD*BOTTOM CHORD101 TO 107 FX 0.001100 108 FY 0.001*TOP CHORD201 TO 207 FX 0.001200 208 FX 0.001LOAD 10 LOADTYPE Seismic-H TITLE SEISMIC (-X)JOINT LOAD*BOTTOM CHORD101 TO 107 FX -0.001100 108 FX -0.001*TOP CHORD201 TO 207 FX -0.001200 208 FX -0.001LOAD 11 LOADTYPE Seismic-V TITLE SEISMIC (-Y)SELFWEIGHT Y -0.057JOINT LOAD*BOTTOM CHORD101 TO 107 FY -0.001100 108 FY -0.001*TOP CHORD201 TO 207 FY -0.001200 208 FY -0.001MEMBER LOAD*BOTTOM CHORD100 TO 107 UNI GY -0.009*TOP CHORD200 TO 207 UNI GY -0.009LOAD COMB 12 D1 1.0LOAD COMB 13 D + L1 1.0 2 1.0LOAD COMB 14 D + LR1 1.0 3 1.0LOAD COMB 15 D + S1 1.0 4 1.0LOAD COMB 16 D + 0.75L + 0.75LR1 1.0 2 0.75 3 0.75LOAD COMB 17 D + 0.75L + 0.75S1 1.0 2 0.75 4 1.0LOAD COMB 18 D + 0.6W(+X)1 1.0 5 0.6 7 0.6LOAD COMB 19 D + 0.6W(-X)1 1.0 6 0.6 7 0.6LOAD COMB 20 D + 0.75L + 0.75[0.6W(+X)] + 0.75LR1 1.0 2 0.75 5 0.45 7 0.45 3 0.75LOAD COMB 21 D + 0.75L + 0.75[0.6W(-X)] + 0.75LR1 1.0 2 0.75 6 0.45 7 0.45 3 0.75LOAD COMB 22 D + 0.75L + 0.75[0.6W(+X)] + 0.75S1 1.0 2 0.75 5 0.45 7 0.45 4 1.0LOAD COMB 23 D + 0.75L + 0.75[0.6W(-X)] + 0.75S1 1.0 2 0.75 6 0.45 7 0.45 4 1.0LOAD COMB 24 0.6D + 0.6W(+X)1 0.6 5 0.6 8 0.6LOAD COMB 25 0.6D + 0.6W(-X)1 0.6 6 0.6 8 0.6LOAD COMB 26 D + 0.7E(+X)1 1.0 9 0.7 11 0.7LOAD COMB 27 D + 0.7E(-X)1 1.0 10 0.7 11 0.7LOAD COMB 28 D + 0.75[0.7E(+X)] + L + S1 1.0 9 0.525 11 0.525 2 1.0 4 1.0LOAD COMB 29 D + 0.75[0.7E(-X)] + L + S1 1.0 10 0.525 11 0.525 2 1.0 4 1.0LOAD COMB 30 0.6D - 0.7E(-Y) + 0.7E(+X)1 0.6 11 -0.7 9 0.7LOAD COMB 31 0.6D - 0.7E(-Y) + 0.7E(-X)1 0.6 11 -0.7 10 0.7PERFORM ANALYSISDEFINE ENVELOPE1 TO 11 ENVELOPE 1 TYPE SERVICEABILITY12 TO 31 ENVELOPE 2 TYPE STRENGTHEND DEFINE ENVELOPELOAD LIST ENV 1 2PARAMETER 1CODE AISC UNIFIED 2016METHOD ASDBEAM 1 ALLRATIO 0.9 ALLFYLD 7200 MEMB 100 TO 107 200 TO 207FYLD 5184 MEMB 300 TO 306 400 TO 407LX 16.5 MEMB 100 TO 107LY 16.5 MEMB 100 TO 107DFF 414 ALLDJ1 100 MEMB 100 TO 107DJ2 108 MEMB 100 TO 107DJ1 200 MEMB 200 TO 207DJ2 208 MEMB 200 TO 207DMIN 0.667 MEMB 100 TO 107DMIN 1 MEMB 200 TO 207DMAX 0.875 MEMB 100 TO 107DMAX 1.75 MEMB 200 TO 207FIXED GROUPGROUP MEMB 100 TO 107GROUP MEMB 200 TO 207GROUP MEMB 300 301 305 306GROUP MEMB 400 401 406 407GROUP MEMB 302 TO 304GROUP MEMB 402 TO 405SELECT OPTIMIZEDPERFORM ANALYSISPARAMETER 2BEAM 1 ALLRATIO 1 ALLTRACK 1 ALLCHECK CODE ALLPRINT SUPPORT REACTION LIST 100 108 200 208PRINT MEMBER FORCES ALLFINISH
Hello,
What is the version number of STAAD.Pro you are using? The only issue I noticed in the model is DJ1 and DJ2 for the top chord. The top chord is not colinear and hance DJ1 and DJ2 will not work properly. Once I omit that 2 parameter, the file runs without any errror in my system with the latest version 22.11.00.156. If you are using any older version please upgrade to the latest version and check.