Can anyone know why I am getting Instability warnings for joints 2, 11, 54 and 63 in STAAD Model below?
Thank you.
STAAD SPACE
START JOB INFORMATION
ENGINEER DATE 16-Aug-16
END JOB INFORMATION
INPUT WIDTH 79
UNIT FEET KIP
JOINT COORDINATES
1 10 0 0; 2 51 0 0; 3 10 0.49 0; 4 51 0.49 0; 5 10 10.1567 0; 6 51 10.1567 0;
7 10 14.99 0; 8 51 14.99 0; 9 10 21.552 0; 10 51 21.552 0; 11 10 24.5 0;
12 51 24.5 0; 13 10 14.99 1.6408; 14 10.8125 14.99 1.6408;
15 16.4375 14.99 1.6408; 16 22.0625 14.99 1.6408; 17 27.6875 14.99 1.6408;
18 33.3125 14.99 1.6408; 19 38.9375 14.99 1.6408; 20 44.5625 14.99 1.6408;
21 50.1875 14.99 1.6408; 22 51 14.99 1.6408; 23 10 21.552 1.6408;
24 10.8125 21.552 1.6408; 25 16.4375 21.552 1.6408; 26 22.0625 21.552 1.6408;
27 27.6875 21.552 1.6408; 28 33.3125 21.552 1.6408; 29 38.9375 21.552 1.6408;
30 44.5625 21.552 1.6408; 31 50.1875 21.552 1.6408; 32 51 21.552 1.6408;
33 10 14.99 8.2033; 34 10.8125 14.99 8.2033; 35 16.4375 14.99 8.2033;
36 22.0625 14.99 8.2033; 37 27.6875 14.99 8.2033; 38 33.3125 14.99 8.2033;
39 38.9375 14.99 8.2033; 40 44.5625 14.99 8.2033; 41 50.1875 14.99 8.2033;
42 51 14.99 8.2033; 43 10 21.552 8.2033; 44 10.8125 21.552 8.2033;
45 16.4375 21.552 8.2033; 46 22.0625 21.552 8.2033; 47 27.6875 21.552 8.2033;
48 33.3125 21.552 8.2033; 49 38.9375 21.552 8.2033; 50 44.5625 21.552 8.2033;
51 50.1875 21.552 8.2033; 52 51 21.552 8.2033; 53 10 0 9.844; 54 51 0 9.844;
55 10 0.49 9.844; 56 51 0.49 9.844; 57 10 5.32333 9.844; 58 51 5.32333 9.844;
59 10 14.99 9.844; 60 51 14.99 9.844; 61 10 21.552 9.844; 62 51 21.552 9.844;
63 10 24.5 9.844; 64 51 24.5 9.844;
MEMBER INCIDENCES
1 1 3; 2 2 4; 3 3 5; 4 4 6; 5 5 7; 6 6 8; 7 7 9; 8 8 10; 9 9 11; 10 10 12;
11 7 13; 12 8 22; 13 9 23; 14 10 32; 15 13 14; 16 14 15; 17 15 16; 18 16 17;
19 17 18; 20 18 19; 21 19 20; 22 20 21; 23 21 22; 24 14 24; 25 24 15; 26 15 26;
27 26 17; 28 17 28; 29 28 19; 30 19 30; 31 30 21; 32 21 31; 33 23 24; 34 24 25;
35 25 26; 36 26 27; 37 27 28; 38 28 29; 39 29 30; 40 30 31; 41 31 32; 42 3 55;
43 4 56; 44 57 3; 45 58 4; 46 5 57; 47 6 58; 48 59 5; 49 60 6; 50 13 33;
51 14 34; 52 14 35; 53 35 16; 54 16 37; 55 37 18; 56 18 39; 57 39 20; 58 20 41;
59 21 41; 60 22 42; 61 15 45; 62 36 26; 63 17 47; 64 38 28; 65 19 49; 66 40 30;
67 23 43; 68 24 44; 69 44 25; 70 25 46; 71 46 27; 72 27 48; 73 48 29; 74 29 50;
75 50 31; 76 31 51; 77 32 52; 78 33 34; 79 34 35; 80 35 36; 81 36 37; 82 37 38;
83 38 39; 84 39 40; 85 40 41; 86 41 42; 87 34 44; 88 34 45; 89 45 36; 90 36 47;
91 47 38; 92 38 49; 93 49 40; 94 40 51; 95 41 51; 96 43 44; 97 44 45; 98 45 46;
99 46 47; 100 47 48; 101 48 49; 102 49 50; 103 50 51; 104 51 52; 105 33 59;
106 42 60; 107 43 61; 108 52 62; 109 53 55; 110 54 56; 111 55 57; 112 56 58;
113 57 59; 114 58 60; 115 59 61; 116 60 62; 117 61 63; 118 62 64;
DEFINE MATERIAL START
ISOTROPIC STEEL
E 4.176e+006
POISSON 0.3
DENSITY 0.489024
ALPHA 6.5e-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 10 109 TO 118 TABLE ST HSSP16X0.375
15 TO 23 33 TO 41 78 TO 86 96 TO 104 TABLE ST PIPS50
24 TO 32 51 TO 59 61 TO 66 68 TO 76 87 TO 95 TABLE ST PIPS30
42 TO 49 TABLE ST L80808
11 TO 14 50 60 67 77 105 TO 108 TABLE ST W10X77
CONSTANTS
MATERIAL STEEL ALL
SUPPORTS
1 2 53 54 PINNED
MEMBER TRUSS
24 TO 32 42 TO 49 51 TO 59 61 TO 66 68 TO 76 87 TO 95
MEMBER RELEASE
11 TO 15 33 78 96 START MY MZ
23 41 86 104 TO 108 END MY MZ
LOAD 1 LOADTYPE Dead TITLE DL
SELFWEIGHT Y -1
UNIT FEET POUND
MEMBER LOAD
78 TO 86 96 TO 104 UNI GY -125
LOAD 2 LOADTYPE None TITLE W_SIGN_PANNEL_NORMAL
MEMBER LOAD
78 TO 86 96 TO 104 UNI GZ 337.25
LOAD 3 LOADTYPE None TITLE W_OSS_NORMAL
MEMBER LOAD
24 TO 32 52 TO 58 61 TO 66 69 TO 75 UNI GZ 11.9
15 TO 23 33 TO 41 UNI GZ 19.84
1 TO 10 109 111 TO 118 UNI GZ 63.48
44 TO 49 UNI GZ 44.97
LOAD 4 LOADTYPE None TITLE W_SIGN_PANNEL_TRANSVERSE
MEMBER LOAD
78 TO 86 96 TO 104 UNI GX 67.45
LOAD 5 LOADTYPE None TITLE W_OSS_TRANSVERSE
MEMBER LOAD
24 TO 32 52 TO 58 61 TO 66 69 TO 75 UNI GX 2.38
15 TO 23 33 TO 41 UNI GX 3.97
1 TO 10 109 111 TO 118 UNI GX 12.7
44 TO 49 UNI GX 8.99
LOAD 6 LOADTYPE None TITLE ICE_SIGN PANNEL
MEMBER LOAD
78 TO 86 96 TO 104 UNI GY -15
LOAD 7 LOADTYPE None TITLE ICE_OSS
MEMBER LOAD
24 TO 32 51 TO 59 61 TO 66 68 TO 76 87 TO 95 UNI GY -2.36
15 TO 23 33 TO 41 78 TO 86 96 TO 104 UNI GY -3.93
1 TO 10 109 TO 118 UNI GY -12.57
42 TO 49 UNI GY -8
11 TO 14 50 60 67 77 105 TO 108 UNI GY -12
LOAD 8 LOADTYPE Temperature TITLE TEMPERATURE
TEMPERATURE LOAD
1 TO 118 TEMP 80 80 80
LOAD 9 LOADTYPE Temperature TITLE FATIGUE
LOAD COMB 10 LOAD GROUP I_DL
1 1.0
LOAD COMB 11 LOAD GROUP IIA_DL+W
1 1.0 2 1.0 3 1.0 4 1.0 5 1.0
LOAD COMB 12 LOAD GROUP IIB_DL+T
1 1.0 8 1.0
LOAD COMB 13 LOAD GROUP IIC_DL+W+T
1 1.0 2 1.0 3 1.0 4 1.0 5 1.0 8 1.0
LOAD COMB 14 LOAD GROUP III_DL+Ice+0.5W
1 1.0 6 1.0 7 1.0 2 0.5 3 0.5 4 0.5 5 0.5
PERFORM ANALYSIS
FINISH