I made a portal frame arrangement with 3 columns in x axis and 3 columns in z axis, 2 levels (Y-axis) are also provided. All separations are 4 m. Beam and column sizes are given as 0.5m x 0.5m concrete. Then I added 0.25 m offset (specifications) in all the beams. Self weight and floor load of 3.75kN/m2 is given in loading. The analysed file is not symmetric. The symmetric beams doesn't have same moment distribution. The staad input file is given below. Please explain me the what I am doing wrong.
STAAD SPACESTART JOB INFORMATIONENGINEER DATE 23-Feb-21END JOB INFORMATIONINPUT WIDTH 79UNIT METER KNJOINT COORDINATES1 0 0 0; 2 4 0 0; 3 0 0 4; 4 4 0 4; 5 0 4 0; 6 4 4 0; 7 0 4 4; 8 4 4 4;9 0 8 0; 10 4 8 0; 11 0 8 4; 12 4 8 4; 13 8 0 0; 14 8 4 0; 15 8 0 4; 16 8 4 4;17 8 8 0; 18 8 8 4; 19 0 0 8; 20 0 4 8; 21 4 0 8; 22 4 4 8; 23 0 8 8; 24 4 8 8;25 8 0 8; 26 8 4 8; 27 8 8 8;MEMBER INCIDENCES1 1 5; 2 2 6; 3 3 7; 4 4 8; 5 5 6; 6 7 8; 7 5 7; 8 6 8; 9 5 9; 10 6 10;11 7 11; 12 8 12; 13 9 10; 14 11 12; 15 9 11; 16 10 12; 17 13 14; 18 15 16;19 6 14; 20 8 16; 21 14 16; 22 14 17; 23 16 18; 24 10 17; 25 12 18; 26 17 18;27 19 20; 28 21 22; 29 20 22; 30 7 20; 31 8 22; 32 20 23; 33 22 24; 34 23 24;35 11 23; 36 12 24; 37 25 26; 38 22 26; 39 16 26; 40 26 27; 41 24 27; 42 18 27;START GROUP DEFINITIONMEMBERFLOOR_BEAMS 5 TO 8 13 TO 16 19 TO 21 24 TO 26 29 TO 31 34 TO 36 38 39 41 42END GROUP DEFINITIONDEFINE MATERIAL STARTISOTROPIC STEELE 2.05e+08POISSON 0.3DENSITY 78.5ALPHA 1.2e-05DAMP 0.03TYPE STEELSTRENGTH FY 253200 FU 407800 RY 1.5 RT 1.2ISOTROPIC CONCRETEE 2.17185e+07POISSON 0.17DENSITY 23.5616ALPHA 1e-05DAMP 0.05TYPE CONCRETESTRENGTH FCU 27579END DEFINE MATERIALMEMBER PROPERTY AMERICAN1 TO 4 9 TO 12 17 18 22 23 27 28 32 33 37 40 PRIS YD 0.5 ZD 0.55 TO 8 13 TO 16 19 TO 21 24 TO 26 29 TO 31 34 TO 36 38 39 41 -42 PRIS YD 0.5 ZD 0.5CONSTANTSMATERIAL CONCRETE ALLSUPPORTS1 TO 4 13 15 19 21 25 PINNEDMEMBER OFFSET5 TO 8 13 TO 16 19 TO 21 24 TO 26 29 TO 31 34 TO 36 38 39 41 -42 START LOCAL 0.25 0 05 TO 8 13 TO 16 19 TO 21 24 TO 26 29 TO 31 34 TO 36 38 39 41 -42 END LOCAL -0.25 0 0LOAD 1 LOADTYPE Dead TITLE DLSELFWEIGHT Y -1 FLOOR LOADYRANGE 0 8 FLOAD -3.75 GYPERFORM ANALYSISFINISH
Based on a preliminary investigation, it seems like deviations are being caused by the floor load when the offset is in there. I have forwarded this issue to our development desk for further investigation. Help Ticket# 555925 has been filed.
Ok.
Hi Sye,
I have a question regarding offset too. Could you please help me to resolve it ?
I am providing two beam size of 230 mm x 380mm and 230mm x 700mm respectively. When I am assigning 700mm as a depth to some set of beam, Beam depth is not flushed with 380mm depth beam as it can be shown in a rendered view.
Why is it so ? Is it a normal practice or I have to flush it by providing offset in Y(Down) Direction?
Center line modeling approach is used in STAAD.Pro, so it is expected that beam tops are not flush if their heights are different. You may use the offset command to make the tops flush. Most of the users use a centerline approach while modeling to keep the model more simple.
Hello good day, I know this is already a late question to this topic, but where does STAAD calculate the force from offseted section? Is it still on its centroid?