STAAD Instability weak spring

Question

Hello, 
 I am getting a weak spring message in this code. I am not able to understand why this is happening. My assumption is that it's because of pinned end supports there is some moment in the frame which is not able to get resolved. If my assumption is right then can someone please help me resolve this. (I can't make any support fixed). 
 Thanks a lot. 
 
 STAAD SPACE START JOB INFORMATION ENGINEER DATE 19-Apr-19 END JOB INFORMATION INPUT WIDTH 79 UNIT FEET KIP JOINT COORDINATES 1 0 0 -0.000399272; 2 0 0 12.6667; 3 0 1 0; 4 0 1 12.6667; 8 0 2 -0.000399272; 9 0 2 7.1667; 10 0 2 12.6667; 15 1.5 2 -0.000399272; 16 1.5 2 12.6667; 24 13.775 2 3.3335; 30 26.05 2 -0.000399272; 31 26.05 2 12.6667; 32 27.55 0 -0.000399272; 33 27.55 0 12.6667; 34 27.55 1 0; 35 27.55 1 12.6667; 39 27.55 2 -0.000399272; 49 27.55 2 11.1667; 50 0 2 11.1667; 51 27.55 2 1.4996; 52 0 2 1.4996; 62 0 2 6.6667; 64 1.5 2 6.6667; 66 26.05 2 6.6667; 67 34.0497 0 7.167; 69 34.0497 0 10.667; 70 34.0497 3.5 10.667; 75 6.8 2 12.6667; 77 27.55 2 6.6667; 79 27.55 2 12.6667; 81 27.55 7 10.6667; 82 6.8 7 12.6667; 90 27.55 7 12.6667; 92 18.8003 2 12.6667; 96 18.8002 7 12.6667; 100 27.55 2 7.1667; 101 34.0497 3.5 7.167; 102 18.8 2 7.1667; 103 6.8 2 7.1667; 104 6.8 7 7.1667; 105 27.55 7 7.1667; 106 18.8 7 7.1667; 110 40.5493 0 7.167; 111 40.5493 0 10.667; 119 12.8003 7 12.6667; 120 18.8 7 6.6667; 121 6.8 7 6.6667; 122 27.55 7 6.6667; 123 12.8 7 6.6667; 124 6.8 6.5 7.1667; 125 27.55 6.5 7.1667; 126 18.8 6.5 7.1667; 127 23.1753 7 12.6667; 128 23.175 7 6.6667; MEMBER INCIDENCES 1 3 1; 2 4 2; 3 8 3; 4 10 4; 5 9 62; 10 9 50; 17 15 3; 18 16 4; 19 8 15; 20 10 16; 35 15 30; 36 100 102; 37 31 92; 47 30 34; 48 31 35; 49 30 39; 50 31 79; 51 34 32; 52 35 33; 53 39 34; 54 79 35; 55 100 77; 61 49 100; 91 49 79; 92 35 49; 93 50 10; 94 4 50; 95 51 39; 96 34 51; 97 52 8; 98 3 52; 104 77 66; 105 77 51; 107 62 52; 108 15 64; 109 64 62; 111 30 66; 112 66 64; 113 67 101; 114 69 70; 118 103 124; 119 75 82; 120 100 125; 121 79 90; 122 105 101; 123 81 70; 125 121 123; 132 81 105; 134 102 126; 135 92 96; 139 90 81; 148 75 16; 150 92 75; 152 102 103; 153 103 9; 154 104 82; 156 106 96; 158 120 128; 161 123 120; 163 101 110; 164 70 111; 165 119 123; 166 82 119; 167 96 127; 168 119 96; 169 105 122; 170 106 120; 172 104 121; 173 124 104; 174 125 105; 175 126 106; 176 124 121; 177 126 120; 179 125 122; 180 127 90; 181 128 122; 182 127 128; 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 132 139 154 156 165 169 170 172 182 TABLE ST C4X5 1 TO 4 51 TO 54 TABLE ST HSST6X6X0.5 MEMBER PROPERTY AMERICAN 17 18 47 48 92 94 96 98 176 177 179 TABLE ST L30308 5 10 19 20 35 TO 37 49 50 55 61 91 93 95 97 104 105 107 TO 109 111 112 148 - 150 152 153 TABLE ST W12X45 125 158 161 166 TO 168 180 181 TABLE ST MC4X13 113 114 118 TO 121 134 135 173 TO 175 TABLE ST HSST3X3X0.375 122 123 163 164 TABLE ST MC10X22 CONSTANTS BETA 45 MEMB 17 18 47 48 92 94 96 98 176 177 179 MATERIAL STEEL ALL SUPPORTS 110 111 FIXED BUT FX MX MY MZ 1 2 32 33 67 69 PINNED 120 TO 122 FIXED BUT FX FY MX MY MZ MEMBER RELEASE 19 20 36 104 108 111 139 165 182 START MY MZ 49 50 108 109 111 153 154 156 165 169 170 172 182 END MY MZ 122 123 START FX MY MZ MEMBER TRUSS 17 18 47 48 92 94 96 98 176 177 179 SLAVE ZX MASTER 24 JOINT 15 30 64 66 LOAD 1 LOADTYPE Dead TITLE DL SELFWEIGHT Y -1 LIST ALL MEMBER LOAD 19 35 49 104 109 112 UNI GY -0.17 156 165 170 182 UNI GY -0.048 132 139 154 169 172 UNI GY -0.024 122 123 163 164 UNI GY -0.014 LOAD 2 LOADTYPE Roof Live TITLE LR MEMBER LOAD 156 165 170 182 UNI GY -0.36 132 139 154 169 172 UNI GY -0.18 122 123 163 164 UNI GY -0.18 LOAD 3 LOADTYPE Roof Live TITLE LRCONC MEMBER LOAD 156 165 170 182 UNI GY -0.36 132 139 154 169 172 UNI GY -0.18 122 CON GY -1 0.5 LOAD 4 LOADTYPE Snow TITLE SL MEMBER LOAD 19 35 49 104 109 112 UNI GY -0.08 156 165 170 182 UNI GY -0.13 132 139 154 169 172 UNI GY -0.065 122 123 163 164 UNI GY 0.04 LOAD 5 LOADTYPE Snow TITLE SL DRIFT MEMBER LOAD 170 TRAP GY -0.1665 -0.18 156 TRAP GY -0.1665 -0.02 165 182 TRAP GY -0.02 -0.18 169 172 TRAP GY -0.08425 -0.09 154 TRAP GY -0.08425 -0.01 132 TRAP GY -0.054 -0.08425 139 TRAP GY -0.01 -0.054 LOAD 6 LOADTYPE Ice TITLE IL MEMBER LOAD 156 165 170 182 UNI GY -0.14 132 139 154 169 172 UNI GY -0.07 122 123 163 164 UNI GY -0.035 19 35 49 104 109 112 UNI GY -0.05 19 35 49 104 109 112 UNI GY -0.042 1 TO 4 51 TO 54 UNI GY -0.022 17 18 47 48 92 94 96 98 176 177 179 UNI GY -0.012 125 132 139 154 156 158 161 165 TO 170 172 180 TO 182 UNI GY -0.013 5 10 19 20 35 TO 37 49 50 55 61 91 93 95 97 104 105 107 TO 109 111 112 148 - 150 152 153 UNI GY -0.04 122 123 163 164 UNI GY -0.025 113 114 118 TO 121 134 135 173 TO 175 UNI GY -0.015 LOAD 7 LOADTYPE Wind TITLE WIND +X MEMBER LOAD 19 35 49 104 109 112 UMOM GZ -0.55 19 35 49 104 109 112 UNI GX 0.12 122 123 163 164 UNI GX 0.009 1 TO 4 UNI GX 0.04 113 114 118 119 173 UNI GX 0.02 154 172 UNI GX 0.03 94 98 176 UNI GX 0.02 5 10 93 97 107 UNI GX 0.08 LOAD 8 LOADTYPE Wind TITLE WIND -X MEMBER LOAD 19 35 49 104 109 112 UMOM GZ 0.55 19 35 49 104 109 112 UNI GX -0.12 122 123 163 164 UNI GX -0.009 51 TO 54 UNI GX -0.04 113 114 120 121 174 UNI GX -0.02 132 139 169 UNI GX -0.03 92 96 179 UNI GX -0.02 55 61 91 95 105 UNI GX -0.08 LOAD 9 LOADTYPE Wind TITLE WIND +Z MEMBER LOAD 19 35 49 104 109 112 UNI GZ 0.42 19 35 49 UNI GY 0.33 104 109 112 UNI GY -0.33 122 163 UNI GZ 0.07 1 3 51 53 UNI GZ 0.022 113 UNI GZ 0.011 17 47 UNI GZ 0.023 19 35 49 UNI GZ 0.09 LOAD 10 LOADTYPE Wind TITLE WIND -Z MEMBER LOAD 19 35 49 104 109 112 UNI GZ -0.42 104 109 112 UNI GY 0.33 19 35 49 UNI GY -0.33 123 164 UNI GZ -0.07 2 4 52 54 UNI GZ -0.022 114 119 121 135 UNI GZ -0.011 18 48 UNI GZ -0.023 20 37 50 148 150 UNI GZ -0.09 166 TO 168 180 UNI GZ -0.03 LOAD 11 LOADTYPE Wind on Ice TITLE WIL+X MEMBER LOAD 122 123 163 164 UNI GX 0.006 1 TO 4 UNI GX 0.009 154 172 UNI GX 0.01 94 98 176 UNI GX 0.005 5 10 93 97 107 UNI GX 0.017 113 114 118 119 173 UNI GX 0.005 LOAD 12 LOADTYPE Wind on Ice TITLE WIL-X MEMBER LOAD 122 123 163 164 UNI GX -0.006 51 TO 54 UNI GX -0.009 113 114 120 121 174 UNI GX -0.005 132 139 169 UNI GX -0.01 92 96 179 UNI GX -0.005 55 61 91 95 105 UNI GX -0.017 LOAD 13 LOADTYPE Wind on Ice TITLE WIL+Z MEMBER LOAD 122 163 UNI GZ 0.02 1 3 51 53 UNI GZ 0.009 113 UNI GZ 0.005 17 47 UNI GZ 0.005 19 35 49 UNI GZ 0.018 LOAD 14 LOADTYPE Wind on Ice TITLE WIL-Z MEMBER LOAD 123 164 UNI GZ -0.02 2 4 52 54 UNI GZ -0.009 114 119 121 135 UNI GZ -0.005 18 48 UNI GZ -0.011 20 37 50 148 150 UNI GZ -0.005 166 TO 168 180 UNI GZ -0.018 LOAD 15 LOADTYPE Seismic TITLE EL+X NOTIONAL LOAD 1 X 0.02 LOAD 16 LOADTYPE Seismic TITLE EL-X NOTIONAL LOAD 1 X -0.02 LOAD 17 LOADTYPE Seismic TITLE EL+Z NOTIONAL LOAD 1 Z 0.002 LOAD 18 LOADTYPE Seismic TITLE EL-Z NOTIONAL LOAD 1 Z -0.02 LOAD 19 LOADTYPE Temperature TITLE TEMP+ LOAD 20 LOADTYPE Temperature TITLE TEMP- LOAD COMB 101 D 1 1.0 LOAD COMB 102 D+LR 1 1.0 2 1.0 LOAD COMB 103 D+LR2 1 1.0 3 1.0 LOAD COMB 104 D+S 1 1.0 4 1.0 5 1.0 LOAD COMB 105 D+0.75LR 1 1.0 2 0.75 LOAD COMB 106 D+0.75LR2 1 1.0 3 0.75 LOAD COMB 107 D+0.75S 1 1.0 4 0.75 5 0.75 LOAD COMB 108 D+WX+ 1 1.0 7 1.0 LOAD COMB 109 D+WX- 1 1.0 8 1.0 LOAD COMB 110 D+WZ+ 1 1.0 9 1.0 LOAD COMB 111 D+WZ- 1 1.0 10 1.0 LOAD COMB 112 D+0.7EX+ 1 1.0 15 0.7 LOAD COMB 113 D+0.7EX- 1 1.0 16 0.7 LOAD COMB 114 D+0.7EZ+ 1 1.0 17 0.7 LOAD COMB 115 D+0.7EZ- 1 1.0 18 0.7 LOAD COMB 116 D+0.75WX++0.75LR 1 1.0 7 0.75 2 0.75 LOAD COMB 117 D+0.75WX-+0.75LR 1 1.0 8 0.75 2 0.75 LOAD COMB 118 D+0.75WZ++0.75LR 1 1.0 9 0.75 2 0.75 LOAD COMB 119 D+0.75WZ-+0.75LR 1 1.0 10 0.75 2 0.75 LOAD COMB 120 D+0.75WX++0.75LR2 1 1.0 7 0.75 3 0.75 LOAD COMB 121 D+0.75WX-+0.75LR2 1 1.0 8 0.75 3 0.75 LOAD COMB 122 D+0.75WZ++0.75LR2 1 1.0 9 0.75 3 0.75 LOAD COMB 123 D+0.75WZ-+0.75LR2 1 1.0 10 0.75 3 0.75 LOAD COMB 124 D+0.75EX++0.75LR 1 1.0 15 0.75 2 0.75 LOAD COMB 125 D+0.75EX-+0.75LR 1 1.0 16 0.75 2 0.75 LOAD COMB 126 D+0.75EZ++0.75LR 1 1.0 17 0.75 2 0.75 LOAD COMB 127 D+0.75EZ-+0.75LR 1 1.0 18 0.75 2 0.75 LOAD COMB 128 D+0.75EX++0.75LR2 1 1.0 15 0.75 3 0.75 LOAD COMB 129 D+0.75EX-+0.75LR2 1 1.0 16 0.75 3 0.75 LOAD COMB 130 D+0.75EZ++0.75LR2 1 1.0 17 0.75 3 0.75 LOAD COMB 131 D+0.75EZ-+0.75LR2 1 1.0 18 0.75 3 0.75 LOAD COMB 132 D+0.75WX++0.75S 1 1.0 7 0.75 4 0.75 5 0.75 LOAD COMB 133 D+0.75WX-+0.75S 1 1.0 8 0.75 4 0.75 5 0.75 LOAD COMB 134 D+0.75WZ++0.75S 1 1.0 9 0.75 4 0.75 5 0.75 LOAD COMB 135 D+0.75WZ-+0.75S 1 1.0 10 0.75 4 0.75 5 0.75 LOAD COMB 136 D+0.525EX++0.75S 1 1.0 15 0.525 4 0.75 5 0.75 LOAD COMB 137 D+0.525EX-+0.75S 1 1.0 16 0.525 4 0.75 5 0.75 LOAD COMB 138 D+0.525EZ++0.75S 1 1.0 17 0.525 4 0.75 5 0.75 LOAD COMB 139 D+0.525EZ-+0.75S 1 1.0 18 0.525 4 0.75 5 0.75 LOAD COMB 140 0.6D+WX+ 1 0.6 7 1.0 LOAD COMB 141 0.6D+WX- 1 0.6 8 1.0 LOAD COMB 142 0.6D+WZ+ 1 0.6 9 1.0 LOAD COMB 143 0.6D+WZ- 1 0.6 10 1.0 LOAD COMB 144 0.6D+0.7EX+ 1 0.6 15 0.7 LOAD COMB 145 0.6D+0.7EX- 1 0.6 16 0.7 LOAD COMB 146 0.6D+0.7EZ+ 1 0.6 17 0.7 LOAD COMB 147 0.6D+0.7EZ- 1 0.6 18 0.7 LOAD COMB 201 D+0.7IL 1 1.0 6 0.7 LOAD COMB 202 D+0.7IL+0.7WILX++S 1 1.0 6 0.7 11 0.7 4 1.0 5 1.0 LOAD COMB 203 D+0.7IL+0.7WILX-+S 1 1.0 6 0.7 12 0.7 4 1.0 5 1.0 LOAD COMB 204 D+0.7IL+0.7WILZ++S 1 1.0 6 0.7 13 0.7 4 1.0 5 1.0 LOAD COMB 205 D+0.7IL+0.7WILZ-+S 1 1.0 6 0.7 14 0.7 4 1.0 5 1.0 LOAD COMB 206 D+0.7IL+0.7WILX+ 1 1.0 6 0.7 11 0.7 LOAD COMB 207 D+0.7IL+0.7WILX- 1 1.0 6 0.7 12 0.7 LOAD COMB 208 D+0.7IL+0.7WILZ+ 1 1.0 6 0.7 13 0.7 LOAD COMB 209 D+0.7IL+0.7WILZ- 1 1.0 6 0.7 14 0.7 LOAD COMB 301 1.4D 1 1.4 LOAD COMB 302 1.2D+0.5LR 1 1.2 2 0.5 LOAD COMB 303 1.2D+0.5LR2 1 1.2 3 0.5 LOAD COMB 304 1.2D+0.5S 1 1.2 4 0.5 5 0.5 LOAD COMB 305 1.2D+1.6LR+0.8WX+ 1 1.2 2 1.6 7 0.8 LOAD COMB 306 1.2D+1.6LR+0.8WX- 1 1.2 2 1.6 8 0.8 LOAD COMB 307 1.2D+1.6LR+0.8WZ+ 1 1.2 2 1.6 9 0.8 LOAD COMB 308 1.2D+1.6LR+0.8WZ- 1 1.2 2 1.6 10 0.8 LOAD COMB 309 1.2D+1.6LR2+0.8WX+ 1 1.2 3 1.6 7 0.8 LOAD COMB 310 1.2D+1.6LR2+0.8WX- 1 1.2 3 1.6 8 0.8 LOAD COMB 311 1.2D+1.6LR2+0.8WZ+ 1 1.2 3 1.6 9 0.8 LOAD COMB 312 1.2D+1.6LR2+0.8WZ- 1 1.2 3 1.6 10 0.8 LOAD COMB 313 1.2D+1.6S+0.8WX+ 1 1.2 4 1.6 5 1.6 7 0.8 LOAD COMB 314 1.2D+1.6S+0.8WX- 1 1.2 4 1.6 5 1.6 8 0.8 LOAD COMB 315 1.2D+1.6S+0.8WZ+ 1 1.2 4 1.6 5 1.6 9 0.8 LOAD COMB 316 1.2D+1.6S+0.8WZ- 1 1.2 4 1.6 5 1.6 10 0.8 LOAD COMB 317 1.2D+0.5LR+1.6WX+ 1 1.2 2 0.5 7 1.6 LOAD COMB 318 1.2D+0.5LR+1.6WX- 1 1.2 2 0.5 8 1.6 LOAD COMB 319 1.2D+0.5LR+1.6WZ+ 1 1.2 2 0.5 9 1.6 LOAD COMB 320 1.2D+0.5LR+1.6WZ- 1 1.2 2 0.5 10 1.6 LOAD COMB 321 1.2D+0.5LR2+1.6WX+ 1 1.2 3 0.5 7 1.6 LOAD COMB 322 1.2D+0.5LR2+1.6WX- 1 1.2 3 0.5 8 1.6 LOAD COMB 323 1.2D+0.5LR2+1.6WZ+ 1 1.2 3 0.5 9 1.6 LOAD COMB 324 1.2D+0.5LR2+1.6WZ- 1 1.2 3 0.5 10 1.6 LOAD COMB 325 1.2D+0.5S+1.6WX+ 1 1.2 4 0.5 5 0.5 7 1.6 LOAD COMB 326 1.2D+0.5S+1.6WX- 1 1.2 4 0.5 5 0.5 8 1.6 LOAD COMB 327 1.2D+0.5S+1.6WZ+ 1 1.2 4 0.5 5 0.5 9 1.6 LOAD COMB 328 1.2D+0.5S+1.6WZ- 1 1.2 4 0.5 5 0.5 10 1.6 LOAD COMB 329 1.2D+EX++0.2S 1 1.2 15 1.0 4 0.2 5 0.2 LOAD COMB 330 1.2D+EX-+0.2S 1 1.2 16 1.0 4 0.2 5 0.2 LOAD COMB 331 1.2D+EZ++0.2S 1 1.2 17 1.0 4 0.2 5 0.2 LOAD COMB 332 1.2D+EZ-+0.2S 1 1.0 18 1.0 4 1.0 5 1.0 LOAD COMB 333 0.9D+1.6WX+ 1 0.9 7 1.6 LOAD COMB 334 0.9D+1.6WX- 1 0.9 8 1.6 LOAD COMB 335 0.9D+1.6WZ+ 1 0.9 9 1.6 LOAD COMB 336 0.9D+1.6WZ- 1 0.9 10 1.6 LOAD COMB 337 0.9D+EX+ 1 0.9 15 1.6 LOAD COMB 338 0.9D+EX- 1 0.9 16 1.6 LOAD COMB 339 0.9D+EZ+ 1 0.9 17 1.6 LOAD COMB 340 0.9D+EZ- 1 0.9 18 1.6 LOAD COMB 401 1.2D+0.2I+0.5S 1 1.2 6 0.2 4 0.5 5 0.5 LOAD COMB 402 1.2D+I+WIX++0.5S 1 1.2 6 1.0 11 1.0 4 0.5 5 0.5 LOAD COMB 403 1.2D+I+WIX-+0.5S 1 1.2 6 1.0 12 1.0 4 0.5 5 0.5 LOAD COMB 404 1.2D+I+WIZ++0.5S 1 1.2 6 1.0 13 1.0 4 0.5 5 0.5 LOAD COMB 405 1.2D+I+WIZ-+0.5S 1 1.2 6 1.0 14 1.0 4 0.5 5 0.5 LOAD COMB 406 0.9D+I+WIX+ 1 0.9 6 1.0 11 1.0 LOAD COMB 407 0.9D+I+WIX- 1 0.9 6 1.0 12 1.0 LOAD COMB 408 0.9D+I+WIZ+ 1 0.9 6 1.0 13 1.0 LOAD COMB 409 0.9D+I+WIZ- 1 0.9 6 1.0 14 1.0 PERFORM ANALYSIS DEFINE ENVELOPE 101 TO 147 201 TO 209 ENVELOPE 1 TYPE SERVICEABILITY 301 TO 340 401 TO 409 ENVELOPE 2 TYPE STRENGTH END DEFINE ENVELOPE LOAD LIST ENV 1 2 PARAMETER 1 CODE AISC UNIFIED 2010 METHOD LRFD FU 9360 MEMB 5 10 19 20 35 TO 37 49 50 55 61 91 93 95 97 104 105 107 TO 109 - 111 112 148 150 152 153 FU 8352 MEMB 1 TO 4 17 18 47 48 51 TO 54 92 94 96 98 113 114 118 TO 123 125 - 132 134 135 139 154 156 158 161 163 TO 168 173 TO 175 180 TO 182 FYLD 7200 MEMB 5 10 19 20 35 TO 37 49 50 55 61 91 93 95 97 104 105 - 107 TO 109 111 112 148 150 152 153 FYLD 6624 MEMB 1 TO 4 51 TO 54 113 114 118 TO 121 134 135 173 TO 175 FYLD 5184 MEMB 17 18 47 48 92 94 96 98 122 123 125 132 139 154 156 158 161 - 163 TO 168 180 TO 182 DJ2 8 MEMB 19 35 49 DJ1 39 MEMB 19 35 49 DJ2 39 MEMB 51 53 DJ1 32 MEMB 51 53 DJ2 1 MEMB 1 3 DJ1 8 MEMB 1 3 DJ2 39 MEMB 55 61 91 95 105 DJ1 79 MEMB 55 61 91 95 105 DJ2 8 MEMB 5 10 93 97 107 DJ1 10 MEMB 5 10 93 97 107 DJ2 9 MEMB 36 152 153 DJ1 100 MEMB 36 152 153 DJ2 62 MEMB 104 109 112 DJ1 77 MEMB 104 109 112 DJ2 33 MEMB 52 54 DJ1 79 MEMB 52 54 DJ2 2 MEMB 2 4 DJ1 10 MEMB 2 4 DJ2 10 MEMB 20 37 50 148 150 DJ1 79 MEMB 20 37 50 148 150 DJ2 111 MEMB 123 164 DJ1 81 MEMB 123 164 DJ2 110 MEMB 122 163 DJ1 105 MEMB 122 163 DJ2 104 MEMB 118 173 DJ1 103 MEMB 118 173 DJ2 106 MEMB 134 175 DJ1 102 MEMB 134 175 DJ2 105 MEMB 120 174 DJ1 100 MEMB 120 174 DFF 360 ALL LZ 7 MEMB 5 10 55 61 91 93 95 97 105 107 LZ 15 MEMB 122 123 163 164 LZ 25 MEMB 19 35 49 104 109 112 LZ 28 MEMB 20 36 37 50 148 150 152 153 LY 28 MEMB 19 20 35 TO 37 49 50 104 109 112 148 150 152 153 LY 13 MEMB 5 10 55 61 91 93 95 97 105 107 LY 12 MEMB 125 158 161 166 TO 168 180 181 LY 7.5 MEMB 122 123 163 164 LY 5.5 MEMB 132 139 154 156 169 170 172 KZ 2 MEMB 1 TO 4 51 TO 54 113 114 118 TO 121 134 135 173 TO 175 KY 2 MEMB 1 TO 4 51 TO 54 113 114 118 TO 121 134 135 173 TO 175 CHECK CODE ALL FINISH

Surojit Ghosh · Answer

There is an orphan node present in this model which is not connected to any other part of the structure. Check node number 24 in this model. When program analyzes the structure, it finds an unconnected node which will cause huge deflection if any load is applied on this node. This results the instability warning messages. Remove this node from the model and you will notice there is no instability messages.