Dear All,
Reference to this topic http://communities.bentley.com/products/structural/structural_analysis___design/f/5932/t/43424.
It’s mentioned that in order to achieve the analysis model for the below figure, You have two options which yields the same results:
- Using offset command to offset the beams which are represented between the same nodes on the analysis model to account for the different elevations of the beams.
- Using Rigid type of master-slave links to tie together the nodes of the slabs and beams which are at different elevations.
After examining both approaches using a similar geometry (reactions are shown below), they yield different results and don’t have the same effect. Please clarify the difference between the two approaches and which is more accurate to use.
The model input is below for reference.
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STAAD SPACE
START JOB INFORMATION
ENGINEER DATE 13-Jul-16
END JOB INFORMATION
INPUT WIDTH 79
UNIT METER KN
JOINT COORDINATES
1 0 0 0; 2 0 7 0; 3 8 7 0; 4 8 0 0; 7 10 0 0; 8 10 6 0; 9 18 8 0; 10 18 6 0;
11 10 8 0; 12 18 0 0; 23 4 7 0; 24 18 7 0; 25 14 8 0; 26 10 7 0; 28 12 6 0;
29 16 6 0; 30 2 7 0; 31 6 7 0;
MEMBER INCIDENCES
1 1 2; 3 3 4; 4 2 23; 7 2 30; 8 7 8; 10 11 25; 12 10 12; 13 8 28; 22 23 3;
24 25 9; 31 28 29; 32 29 10; 33 11 28; 34 28 25; 35 25 29; 36 29 9; 37 8 26;
38 10 24; 39 30 31; 40 31 3; 41 2 30; 42 30 23; 43 23 31; 44 31 3;
SUPPORTS
1 4 7 12 FIXED
MEMBER OFFSET
7 39 40 42 44 START 0 -1 0
7 39 TO 41 43 END 0 -1 0
4 22 41 43 START 0 1 0
4 22 42 44 END 0 1 0
DEFINE MATERIAL START
ISOTROPIC STEEL
E 2.05e+008
POISSON 0.3
DENSITY 76.8195
ALPHA 1.2e-005
DAMP 0.03
TYPE STEEL
STRENGTH FY 253200 FU 407800 RY 1.5 RT 1.2
END DEFINE MATERIAL
MEMBER PROPERTY EUROPEAN
1 3 4 7 8 10 12 13 22 24 31 TO 44 TABLE ST 101.6X5CHS
CONSTANTS
MATERIAL STEEL ALL
SLAVE RIGID MASTER 24 JOINT 9 10 24
SLAVE RIGID MASTER 26 JOINT 8 11 26
LOAD 1 LOADTYPE None TITLE LOAD CASE 1
MEMBER LOAD
4 10 22 24 UNI GY -10
1 8 37 UNI GX 5
PERFORM ANALYSIS
FINISH