I'm trying to crosscheck a AISC design example regarding the DIRECT METHOD ANALYSIS.
My problem is that, if I check the moments and the displacements obtained by the Staad Model, I cannot get the same results given in the example.
Could anybody have a look and let me know where in my mistake in the staad model?
Here below both the staad model, while the the pdf reporting the AISC design example C.1A is given as attachment.
Many thanks in advance
Giorgio
STAAD SPACESTART JOB INFORMATIONENGINEER DATE 11-Dec-09END JOB INFORMATIONINPUT WIDTH 79UNIT FEET KIPJOINT COORDINATES1 0 0 0; 2 0 20 0; 3 0 4 0; 4 0 8 0; 5 0 12 0; 6 0 16 0; 7 30 0 0; 8 30 4 0;9 30 8 0; 10 30 12 0; 11 30 16 0; 12 30 20 0; 13 45 0 0; 14 45 4 0; 15 45 8 0;16 45 12 0; 17 45 16 0; 18 45 20 0; 19 7.5 20 0; 20 15 20 0; 21 22.5 20 0;22 33.75 20 0; 23 37.5 20 0; 24 41.25 20 0;MEMBER INCIDENCES1 1 3; 2 3 4; 3 4 5; 4 5 6; 5 6 2; 6 7 8; 7 8 9; 8 9 10; 9 10 11; 10 11 12;11 2 19; 12 13 14; 13 14 15; 14 15 16; 15 16 17; 16 17 18; 17 12 22; 18 19 20;19 20 21; 20 21 12; 21 22 23; 22 23 24; 23 24 18;DEFINE MATERIAL STARTISOTROPIC STEELE 4.28151e+006POISSON 0.3DENSITY 0.489024ALPHA 1.2e-005DAMP 0.03G 1.64674e+006TYPE STEELSTRENGTH FY 5288.19 FU 8517.08 RY 1.5 RT 1.2END DEFINE MATERIALMEMBER PROPERTY AMERICAN1 TO 10 12 TO 16 TABLE ST W12X6511 17 TO 23 TABLE ST W18X40CONSTANTSMATERIAL STEEL ALLSUPPORTS1 7 13 PINNEDMEMBER RELEASE17 START MY MZ23 END MY MZDEFINE DIRECT ANALYSISFLEX 1 ALL*FYLD 6500 LIST ALLAXIAL ALLNOTIONAL LOAD FACTOR 0.002ENDLOAD 1MEMBER LOAD11 18 TO 20 UNI GY -2.4JOINT LOAD2 12 FY -3618 FY -144*LOAD 2NOTIONAL LOAD1 X 0.002 LOAD 10REPEAT LOAD1 1.0 2 1.0 PERFORM ANALYSIS PRINT ALLCHANGELOAD 20REPEAT LOAD1 1.0 2 1.0 PERFORM DIRECT ANALYSIS LRFD PRINT LOAD DATAFINISH