cgstrucg
Structural
- Mar 21, 2018
- 135
Hello,
I am designing a rooftop dunnage structure in staad pro. In my case, I have beams which are on top of one another in perpendicular directions. So I created a thick post between those beams to act like a stub which has no significance so I modeled it really thick. There will be a pin connection between these beams so I released My and Mz for top beams at start and end to not transfer any moment and just shear and axial. I also don't want the stub to transfer any moment to the beam below as there will actually be no moment caused by the top beams on bottom beams in the real scenario as it's a pin joint. So I released My and Mz at the start and end of these stubs. In doing so, I am getting various instabilities. Can someone please help me rectify these.
Thanks
STAAD SPACE
START JOB INFORMATION
ENGINEER DATE 19-Apr-19
END JOB INFORMATION
INPUT WIDTH 79
UNIT FEET KIP
JOINT COORDINATES
1 0 0 0; 2 0 0 27.083; 3 5 0 0; 4 5 0 27.083; 5 12.7917 0 0;
6 12.7917 0 27.083; 7 0 0 4.51383; 8 0 0 9.02767; 9 0 0 13.5415;
10 0 0 18.0553; 11 0 0 22.5692; 12 5 0 4.51383; 13 5 0 9.02767; 14 5 0 13.5415;
15 5 0 18.0553; 16 5 0 22.5692; 17 0 -1 0; 18 0 -1 27.083; 19 5 -1 0;
20 5 -1 27.083; 21 12.7917 -1 0; 22 12.7917 -1 27.083; 23 0 -3 0;
24 12.7917 -3 0; 25 12.7917 -3 27.083; 26 0 -3 27.083; 27 12.7917 0 0.75;
28 0 0 0.75; 29 12.7917 0 26.333; 30 0 0 26.333;
MEMBER INCIDENCES
1 1 28; 2 3 12; 3 5 27; 4 3 1; 5 4 2; 6 7 8; 7 8 9; 8 9 10; 9 10 11; 10 11 30;
11 12 13; 12 13 14; 13 14 15; 14 15 16; 15 16 4; 16 7 12; 17 8 13; 18 9 14;
19 10 15; 20 11 16; 21 1 17; 22 2 18; 23 3 19; 24 4 20; 25 5 21; 26 6 22;
27 17 19; 28 19 21; 29 18 20; 30 20 22; 31 17 23; 32 21 24; 33 22 25; 34 18 26;
35 27 29; 36 27 21; 37 28 7; 38 28 17; 39 29 6; 40 29 22; 41 30 2; 42 30 18;
DEFINE MATERIAL START
ISOTROPIC STEEL
E 4.176e+006
POISSON 0.3
DENSITY 0.489024
ALPHA 6e-006
DAMP 0.03
TYPE STEEL
STRENGTH FY 5184 FU 8352 RY 1.5 RT 1.2
END DEFINE MATERIAL
MEMBER PROPERTY AMERICAN
1 TO 3 6 TO 15 27 TO 30 35 37 39 41 TABLE ST W12X26
4 5 16 TO 20 TABLE ST MC6X18
31 TO 34 TABLE ST HSST4X4X0.5
MEMBER PROPERTY AMERICAN
21 TO 26 PRIS YD 0.75 ZD 0.75
MEMBER PROPERTY AMERICAN
36 38 40 42 TABLE ST L40408
CONSTANTS
MATERIAL STEEL ALL
SUPPORTS
23 TO 26 PINNED
MEMBER RELEASE
1 TO 5 16 TO 26 31 TO 34 36 38 40 42 START MY MZ
4 5 15 TO 26 36 38 TO 42 END MY MZ
LOAD 1 LOADTYPE Dead TITLE DL
MEMBER LOAD
2 3 11 TO 15 35 39 UNI GY -0.22
SELFWEIGHT Y -1 LIST 1 TO 7 10 TO 18 20 27 TO 34
MEMBER LOAD
16 TO 18 20 UNI GY -0.036
4 5 UNI GY -0.018
*LOAD 2 LOADTYPE Roof Live TITLE LL
*MEMBER LOAD
*16 TO 20 UNI GY -0.18
*4 5 UNI GY -0.09
*LOAD 3 LOADTYPE Snow TITLE SL
*MEMBER LOAD
*2 11 TO 15 35 UNI GY -0.082
*16 TO 20 UNI GY -0.095
*4 5 UNI GY -0.048
*LOAD 4 LOADTYPE Snow TITLE SL DRIFT
*MEMBER LOAD
*16 TO 20 LIN Y -0.034 -0.135
*4 5 LIN Y -0.067 -0.017
*LOAD 5 LOADTYPE Ice TITLE IL
*MEMBER LOAD
*16 TO 20 UNI GY -0.084
*4 5 UNI GY -0.042
*31 TO 34 UNI GY -0.0033
*36 38 40 42 UNI GY -0.004
*4 5 16 TO 20 UNI GY -0.017
*1 3 6 TO 10 13 TO 15 27 TO 30 35 37 39 41 UNI GY -0.009
*LOAD 6 LOADTYPE Wind TITLE WIND +X
*MEMBER LOAD
*2 11 TO 15 35 UNI GX 0.335
*1 6 TO 10 37 41 UNI GX 0.044
*31 34 38 42 UNI GX 0.015
*35 UMOM GZ -3.62
*2 11 TO 15 UMOM GZ -1.12
*LOAD 7 LOADTYPE Wind TITLE WIND -X
*MEMBER LOAD
*2 11 TO 15 35 UNI GX -0.335
*3 35 39 UNI GX -0.044
*32 33 36 40 UNI GX -0.015
*35 UMOM GZ 3.62
*2 11 TO 15 UMOM GZ 1.12
*LOAD 8 LOADTYPE Wind TITLE WIND +Z
*MEMBER LOAD
*27 28 UNI GZ 0.047
*31 32 UNI GZ 0.016
*4 UNI GZ 0.024
*LOAD 9 LOADTYPE Wind TITLE WIND -Z
*MEMBER LOAD
*29 30 UNI GZ -0.047
*33 34 UNI GZ -0.016
*5 UNI GZ -0.024
*LOAD 10 LOADTYPE Wind on Ice TITLE WIL +X
*LOAD 11 LOADTYPE Wind on Ice TITLE WIL -X
*LOAD 12 LOADTYPE Wind on Ice TITLE WIL +Z
*LOAD 13 LOADTYPE Wind on Ice TITLE WIL -Z
PERFORM ANALYSIS
PARAMETER 1
CODE AISC UNIFIED 2010
FU 9360 MEMB 1 TO 20 27 TO 30 35 TO 42
FU 8352 MEMB 31 TO 34
FYLD 7200 MEMB 1 TO 20 27 TO 30 35 TO 42
FYLD 6624 MEMB 31 TO 34
UNT 0 MEMB 1 TO 20 35 37 39 41
CHECK CODE MEMB 1 TO 20 27 TO 42
FINISH
I am designing a rooftop dunnage structure in staad pro. In my case, I have beams which are on top of one another in perpendicular directions. So I created a thick post between those beams to act like a stub which has no significance so I modeled it really thick. There will be a pin connection between these beams so I released My and Mz for top beams at start and end to not transfer any moment and just shear and axial. I also don't want the stub to transfer any moment to the beam below as there will actually be no moment caused by the top beams on bottom beams in the real scenario as it's a pin joint. So I released My and Mz at the start and end of these stubs. In doing so, I am getting various instabilities. Can someone please help me rectify these.
Thanks
STAAD SPACE
START JOB INFORMATION
ENGINEER DATE 19-Apr-19
END JOB INFORMATION
INPUT WIDTH 79
UNIT FEET KIP
JOINT COORDINATES
1 0 0 0; 2 0 0 27.083; 3 5 0 0; 4 5 0 27.083; 5 12.7917 0 0;
6 12.7917 0 27.083; 7 0 0 4.51383; 8 0 0 9.02767; 9 0 0 13.5415;
10 0 0 18.0553; 11 0 0 22.5692; 12 5 0 4.51383; 13 5 0 9.02767; 14 5 0 13.5415;
15 5 0 18.0553; 16 5 0 22.5692; 17 0 -1 0; 18 0 -1 27.083; 19 5 -1 0;
20 5 -1 27.083; 21 12.7917 -1 0; 22 12.7917 -1 27.083; 23 0 -3 0;
24 12.7917 -3 0; 25 12.7917 -3 27.083; 26 0 -3 27.083; 27 12.7917 0 0.75;
28 0 0 0.75; 29 12.7917 0 26.333; 30 0 0 26.333;
MEMBER INCIDENCES
1 1 28; 2 3 12; 3 5 27; 4 3 1; 5 4 2; 6 7 8; 7 8 9; 8 9 10; 9 10 11; 10 11 30;
11 12 13; 12 13 14; 13 14 15; 14 15 16; 15 16 4; 16 7 12; 17 8 13; 18 9 14;
19 10 15; 20 11 16; 21 1 17; 22 2 18; 23 3 19; 24 4 20; 25 5 21; 26 6 22;
27 17 19; 28 19 21; 29 18 20; 30 20 22; 31 17 23; 32 21 24; 33 22 25; 34 18 26;
35 27 29; 36 27 21; 37 28 7; 38 28 17; 39 29 6; 40 29 22; 41 30 2; 42 30 18;
DEFINE MATERIAL START
ISOTROPIC STEEL
E 4.176e+006
POISSON 0.3
DENSITY 0.489024
ALPHA 6e-006
DAMP 0.03
TYPE STEEL
STRENGTH FY 5184 FU 8352 RY 1.5 RT 1.2
END DEFINE MATERIAL
MEMBER PROPERTY AMERICAN
1 TO 3 6 TO 15 27 TO 30 35 37 39 41 TABLE ST W12X26
4 5 16 TO 20 TABLE ST MC6X18
31 TO 34 TABLE ST HSST4X4X0.5
MEMBER PROPERTY AMERICAN
21 TO 26 PRIS YD 0.75 ZD 0.75
MEMBER PROPERTY AMERICAN
36 38 40 42 TABLE ST L40408
CONSTANTS
MATERIAL STEEL ALL
SUPPORTS
23 TO 26 PINNED
MEMBER RELEASE
1 TO 5 16 TO 26 31 TO 34 36 38 40 42 START MY MZ
4 5 15 TO 26 36 38 TO 42 END MY MZ
LOAD 1 LOADTYPE Dead TITLE DL
MEMBER LOAD
2 3 11 TO 15 35 39 UNI GY -0.22
SELFWEIGHT Y -1 LIST 1 TO 7 10 TO 18 20 27 TO 34
MEMBER LOAD
16 TO 18 20 UNI GY -0.036
4 5 UNI GY -0.018
*LOAD 2 LOADTYPE Roof Live TITLE LL
*MEMBER LOAD
*16 TO 20 UNI GY -0.18
*4 5 UNI GY -0.09
*LOAD 3 LOADTYPE Snow TITLE SL
*MEMBER LOAD
*2 11 TO 15 35 UNI GY -0.082
*16 TO 20 UNI GY -0.095
*4 5 UNI GY -0.048
*LOAD 4 LOADTYPE Snow TITLE SL DRIFT
*MEMBER LOAD
*16 TO 20 LIN Y -0.034 -0.135
*4 5 LIN Y -0.067 -0.017
*LOAD 5 LOADTYPE Ice TITLE IL
*MEMBER LOAD
*16 TO 20 UNI GY -0.084
*4 5 UNI GY -0.042
*31 TO 34 UNI GY -0.0033
*36 38 40 42 UNI GY -0.004
*4 5 16 TO 20 UNI GY -0.017
*1 3 6 TO 10 13 TO 15 27 TO 30 35 37 39 41 UNI GY -0.009
*LOAD 6 LOADTYPE Wind TITLE WIND +X
*MEMBER LOAD
*2 11 TO 15 35 UNI GX 0.335
*1 6 TO 10 37 41 UNI GX 0.044
*31 34 38 42 UNI GX 0.015
*35 UMOM GZ -3.62
*2 11 TO 15 UMOM GZ -1.12
*LOAD 7 LOADTYPE Wind TITLE WIND -X
*MEMBER LOAD
*2 11 TO 15 35 UNI GX -0.335
*3 35 39 UNI GX -0.044
*32 33 36 40 UNI GX -0.015
*35 UMOM GZ 3.62
*2 11 TO 15 UMOM GZ 1.12
*LOAD 8 LOADTYPE Wind TITLE WIND +Z
*MEMBER LOAD
*27 28 UNI GZ 0.047
*31 32 UNI GZ 0.016
*4 UNI GZ 0.024
*LOAD 9 LOADTYPE Wind TITLE WIND -Z
*MEMBER LOAD
*29 30 UNI GZ -0.047
*33 34 UNI GZ -0.016
*5 UNI GZ -0.024
*LOAD 10 LOADTYPE Wind on Ice TITLE WIL +X
*LOAD 11 LOADTYPE Wind on Ice TITLE WIL -X
*LOAD 12 LOADTYPE Wind on Ice TITLE WIL +Z
*LOAD 13 LOADTYPE Wind on Ice TITLE WIL -Z
PERFORM ANALYSIS
PARAMETER 1
CODE AISC UNIFIED 2010
FU 9360 MEMB 1 TO 20 27 TO 30 35 TO 42
FU 8352 MEMB 31 TO 34
FYLD 7200 MEMB 1 TO 20 27 TO 30 35 TO 42
FYLD 6624 MEMB 31 TO 34
UNT 0 MEMB 1 TO 20 35 37 39 41
CHECK CODE MEMB 1 TO 20 27 TO 42
FINISH
