Hello everyone, I have modeled a two-story structure and realized some irregularities when using the master slave command. When I run the analysis of the structure with the master and slave nodes I have observed the following irregularities in the post processing mode (under the tab Beam - Graphs) :
-The max moment (Mz) experienced by all the columns is the exactly the same, which shouldn't be based on the geometry of the system.
-The max axial load (Fx) on the columns are roughly the same, with some exterior columns having higher axial loads than the interior columns, which is very strange.
-The maximum node displacement is 23.614 mm (more of an observation rather than an irregularity).
When I run the model without the master slave these irregularities do not occur, but the maximum node displacement becomes significantly higher in this model (59.527mm)
Does anyone have an idea as to why these irregularities occur and how can they be fixed.
NB: The Staad editor description is below.
STAAD SPACE
START JOB INFORMATION
ENGINEER DATE 14-Sep-15
END JOB INFORMATION
INPUT WIDTH 79
UNIT METER KN
JOINT COORDINATES
1 -8.534 0 0; 2 -8.534 0 6.096; 3 -8.534 0 12.192; 5 -8.534 4.831 0;
6 -8.534 4.831 6.096; 7 -8.534 4.831 12.192; 9 -8.534 8.5 0;
10 -8.534 8.5 6.096; 11 -8.534 8.5 12.192; 12 0 0 0; 13 0 0 6.096;
14 0 0 12.192; 16 0 4.831 0; 17 0 4.831 6.096; 18 0 4.831 12.192; 20 0 8.5 0;
21 0 8.5 6.096; 22 0 8.5 12.192; 23 7.315 0 0; 24 7.315 0 6.096;
25 7.315 0 12.192; 27 7.315 4.831 0; 28 7.315 4.831 6.096;
29 7.315 4.831 12.192; 32 7.315 8.5 0; 33 7.315 8.5 6.096; 34 7.315 8.5 12.192;
36 14.63 0 0; 37 14.63 0 6.096; 38 14.63 0 12.192; 40 14.63 4.831 0;
41 14.63 4.831 6.096; 42 14.63 4.831 12.192; 45 14.63 8.5 0;
46 14.63 8.5 6.096; 47 14.63 8.5 12.192; 49 21.945 0 0; 50 21.945 0 6.096;
51 21.945 0 12.192; 52 21.945 4.831 0; 53 21.945 4.831 6.096;
54 21.945 4.831 12.192; 55 21.945 8.5 0; 56 21.945 8.5 6.096;
57 21.945 8.5 12.192; 58 29.26 0 0; 59 29.26 0 6.096; 60 29.26 0 12.192;
61 29.26 4.831 0; 62 29.26 4.831 6.096; 63 29.26 4.831 12.192; 64 29.26 8.5 0;
65 29.26 8.5 6.096; 66 29.26 8.5 12.192;
MEMBER INCIDENCES
1 1 5; 2 2 6; 3 3 7; 4 5 6; 5 6 7; 6 5 9; 7 6 10; 8 7 11; 9 9 10; 10 10 11;
11 16 5; 12 6 17; 13 7 18; 14 20 9; 15 10 21; 16 11 22; 17 12 16; 18 13 17;
19 14 18; 20 17 16; 21 18 17; 22 16 20; 23 17 21; 24 18 22; 25 21 20; 26 22 21;
27 16 27; 28 17 28; 29 29 18; 30 20 32; 31 21 33; 33 23 27; 34 24 28; 35 25 29;
36 27 28; 37 28 29; 38 27 32; 39 28 33; 40 29 34; 41 32 33; 42 33 34; 43 27 40;
44 28 41; 45 42 29; 46 32 45; 47 33 46; 48 47 34; 49 36 40; 50 37 41; 51 38 42;
52 40 41; 53 41 42; 54 40 45; 55 41 46; 56 42 47; 57 45 46; 58 46 47; 59 40 52;
60 41 53; 61 54 42; 63 46 56; 64 57 47; 65 49 52; 66 50 53; 67 51 54; 68 52 53;
69 53 54; 70 52 55; 71 53 56; 72 54 57; 73 55 56; 74 56 57; 75 52 61; 76 53 62;
77 63 54; 78 55 64; 79 56 65; 80 66 57; 81 58 61; 82 59 62; 83 60 63; 84 61 62;
85 62 63; 86 61 64; 87 62 65; 88 63 66; 89 64 65; 90 65 66;
DEFINE MATERIAL START
ISOTROPIC CONCRETE
E 2.17185e+007
POISSON 0.17
DENSITY 23.5616
ALPHA 1e-005
DAMP 0.05
TYPE CONCRETE
STRENGTH FCU 27579
END DEFINE MATERIAL
MEMBER PROPERTY AMERICAN
1 TO 3 6 TO 8 17 TO 19 22 TO 24 33 TO 35 38 TO 40 49 TO 51 54 TO 56 -
65 TO 67 70 TO 72 81 TO 83 86 TO 88 PRIS YD 0.45 ZD 0.45
4 5 9 TO 16 20 21 25 TO 31 36 37 41 TO 48 52 53 57 TO 61 63 64 68 69 -
73 TO 80 84 85 89 90 PRIS YD 0.5 ZD 0.45
CONSTANTS
MATERIAL CONCRETE ALL
MEMBER CRACKED
1 TO 3 6 TO 8 17 TO 19 22 TO 24 33 TO 35 38 TO 40 49 TO 51 54 TO 56 -
65 TO 67 70 TO 72 81 TO 83 86 TO 87 -
88 REDUCTION RAX 0.700000 RIX 0.700000 RIY 0.700000 RIZ 0.700000
4 5 9 TO 16 20 21 25 TO 31 36 37 41 TO 48 52 53 57 TO 61 63 64 68 69 -
73 TO 80 84 85 89 -
90 REDUCTION RAX 0.350000 RIX 0.350000 RIY 0.350000 RIZ 0.350000
SUPPORTS
1 TO 3 12 TO 14 23 TO 25 36 TO 38 49 TO 51 58 TO 60 FIXED
SLAVE RIGID MASTER 63 JOINT 5 TO 7 16 TO 18 27 TO 29 40 TO 42 52 TO 54 61 62
SLAVE RIGID MASTER 66 JOINT 9 TO 11 20 TO 22 32 TO 34 45 TO 47 55 TO 57 64 65
DEFINE IBC 2012
SS 1.1 S1 0.375 I 1.5 RX 8 RZ 8 SCLASS 4 CT 0.0466 PX 0.2943 PZ 0.2943 TL 12 -
FA 1.06 FV 1.65 K 0.9
SELFWEIGHT 1
MEMBER WEIGHT
4 5 9 10 84 85 89 90 UNI 20.21
11 13 14 16 UNI 23.14
12 15 UNI 30.13
20 25 36 41 53 58 69 74 UNI 23.44
44 47 76 79 UNI 27.34
27 29 30 61 64 77 80 UNI 21.92
43 46 75 78 UNI 25.52
45 48 UNI 27.59
28 31 60 63 UNI 37.29
21 26 37 42 52 57 68 73 UNI 33.39
59 UNI 11.99
LOAD 1 LOADTYPE Seismic TITLE EQ +X
IBC LOAD X 1 DEC 0 ACC 0
PDELTA ANALYSIS SMALLDELTA PRINT LOAD DATA
CHANGE
LOAD 2 LOADTYPE Seismic TITLE EQ -X
IBC LOAD X -1 DEC 0 ACC 0
PDELTA ANALYSIS SMALLDELTA PRINT LOAD DATA
CHANGE
LOAD 3 LOADTYPE Seismic TITLE EQ +Z
IBC LOAD Z 1 DEC 0 ACC 0
PDELTA ANALYSIS SMALLDELTA PRINT LOAD DATA
CHANGE
LOAD 4 LOADTYPE Seismic TITLE EQ -Z
IBC LOAD Z -1 DEC 0 ACC 0
PDELTA ANALYSIS SMALLDELTA PRINT LOAD DATA
CHANGE
LOAD 5 LOADTYPE Dead TITLE DEAD LOAD
MEMBER LOAD
4 5 9 10 84 85 89 90 UNI GY -20.21
11 13 14 16 UNI GY -23.14
12 15 UNI GY -30.13
20 25 36 41 53 58 69 74 UNI GY -23.44
44 47 76 79 UNI GY -27.34
27 29 30 61 64 77 80 UNI GY -21.92
43 46 75 78 UNI GY -25.52
45 48 UNI GY -27.59
28 31 60 63 UNI GY -37.29
21 26 37 42 52 57 68 73 UNI GY -33.39
59 UNI GY -11.99
SELFWEIGHT Y -1
PDELTA ANALYSIS SMALLDELTA PRINT LOAD DATA
CHANGE
LOAD 6 LOADTYPE Live REDUCIBLE TITLE LIVE LOAD
MEMBER LOAD
4 5 9 10 84 85 89 90 UNI GY -3.66
11 13 14 16 UNI GY -7.51
12 15 UNI GY -15.01
27 29 30 59 61 64 77 80 UNI GY -6.81
43 46 75 78 UNI GY -7.69
20 21 25 26 36 37 41 42 52 53 57 58 68 69 73 74 UNI GY -7.32
28 31 44 47 60 63 76 79 UNI GY -13.62
45 48 UNI GY -9.63
PDELTA ANALYSIS SMALLDELTA PRINT LOAD DATA
CHANGE
LOAD 17 LOADTYPE None TITLE 1.4DL
REPEAT LOAD
5 1.4
LOAD 18 LOADTYPE None TITLE 1.2DL + 1.6LL
REPEAT LOAD
5 1.2 6 1.6
LOAD 19 LOADTYPE None TITLE 1.2DL + 0.5LL
REPEAT LOAD
5 1.2 6 0.5
LOAD 20 LOADTYPE None TITLE 1.2DL + 1EQ+X + 0.5LL
REPEAT LOAD
5 1.2 6 0.5 1 1.0
LOAD 21 LOADTYPE None TITLE 1.2DL + 1EQ-X + 0.5LL
REPEAT LOAD
2 1.0 5 1.2 6 0.5
LOAD 22 LOADTYPE None TITLE 1.2DL + 1EQ+Z + 0.5LL
REPEAT LOAD
3 1.0 5 1.2 6 0.5
LOAD 23 LOADTYPE None TITLE 1.2DL + 1EQ-Z + 0.5LL
REPEAT LOAD
4 1.0 5 1.2 6 0.5
LOAD 24 LOADTYPE None TITLE 0.9DL + 1EQ+X
REPEAT LOAD
1 1.0 5 0.9
LOAD 25 LOADTYPE None TITLE 0.9DL + 1EQ-X
REPEAT LOAD
2 1.0 5 0.9
LOAD 26 LOADTYPE None TITLE 0.9DL + 1EQ+Z
REPEAT LOAD
3 1.0 5 0.9
LOAD 27 LOADTYPE None TITLE 0.9DL + 1EQ-Z
REPEAT LOAD
4 1.0 5 0.9
PDELTA 30 ANALYSIS SMALLDELTA
CHANGE
PERFORM ANALYSIS PRINT ALL
START CONCRETE DESIGN
CODE ACI
MAXMAIN 25 ALL
MINMAIN 25 ALL
MINSEC 10 ALL
RHOMN 0.01 MEMB 1 TO 3 6 TO 8 17 TO 19 22 TO 24 33 TO 35 38 TO 40 49 TO 51 -
54 TO 56 65 TO 67 70 TO 72 81 TO 83 86 TO 88
DESIGN BEAM 4 5 9 TO 16 20 21 25 TO 31 36 37 41 TO 48 52 53 57 TO 61 63 64 -
68 69 73 TO 80 84 85 89 90
DESIGN COLUMN 1 TO 3 6 TO 8 17 TO 19 22 TO 24 33 TO 35 38 TO 40 49 TO 51 54 -
55 TO 56 65 TO 67 70 TO 72 81 TO 83 86 TO 88
MINMAIN 32 ALL
END CONCRETE DESIGN
PRINT STORY DRIFT 0.010000
FINISH