ROOF STRUCTURE -MEMBER FAILURE

[fatihash]

Hi
I have attached a staad file for roof structure , which is at level 169 m of building roof .
But it shows member failure ,showing HSS TORSION and I am not able to find out the reason , plz help.

STAAD SPACE FRAME
START JOB INFORMATION
ENGINEER DATE 1-Feb-18
END JOB INFORMATION
INPUT WIDTH 79
UNIT METER KN
JOINT COORDINATES
4 0 0 1.55; 5 0.975 0 1.55; 7 0 2 0; 8 0.975 2 0; 9 1.45 2 0; 10 0 2 1.55;
11 0.975 2 1.55; 12 1.45 2 1.55; 13 0 4 0; 14 0.975 4 0; 15 1.45 4 0;
16 0 4 1.55; 17 0.975 4 1.55; 18 1.45 4 1.55; 19 0 6 0; 20 0.975 6 0;
21 1.45 6 0; 22 0 6 1.55; 23 0.975 6 1.55; 24 1.45 6 1.55; 25 0 7.42 0;
26 0.975 7.42 0; 27 1.45 7.42 0; 28 0 7.42 1.55; 29 0.975 7.42 1.55;
30 1.45 7.42 1.55; 31 0 0 3.7; 32 0.975 0 3.7; 33 0 2 3.7; 34 0.975 2 3.7;
35 1.45 2 3.7; 36 0 4 3.7; 37 0.975 4 3.7; 38 1.45 4 3.7; 39 0 6 3.7;
40 0.975 6 3.7; 41 1.45 6 3.7; 42 0 7.42 3.7; 43 0.975 7.42 3.7;
44 1.45 7.42 3.7; 45 0 0 5.05; 46 0.975 0 5.05; 47 0 2 5.05; 48 0.975 2 5.05;
49 1.45 2 5.05; 50 0 4 5.05; 51 0.975 4 5.05; 52 1.45 4 5.05; 53 0 6 5.05;
54 0.975 6 5.05; 55 1.45 6 5.05; 56 0 7.42 5.05; 57 0.975 7.42 5.05;
58 1.45 7.42 5.05; 59 0 0 7.2; 60 0.975 0 7.2; 61 0 2 7.2; 62 0.975 2 7.2;
63 1.45 2 7.2; 64 0 4 7.2; 65 0.975 4 7.2; 66 1.45 4 7.2; 67 0 6 7.2;
68 0.975 6 7.2; 69 1.45 6 7.2; 70 0 7.42 7.2; 71 0.975 7.42 7.2;
72 1.45 7.42 7.2; 73 0 0 8.55; 74 0.975 0 8.55; 75 0 2 8.55; 76 0.975 2 8.55;
77 1.45 2 8.55; 78 0 4 8.55; 79 0.975 4 8.55; 80 1.45 4 8.55; 81 0 6 8.55;
82 0.975 6 8.55; 83 1.45 6 8.55; 84 0 7.42 8.55; 85 0.975 7.42 8.55;
86 1.45 7.42 8.55; 87 0 0 10.7; 88 0.975 0 10.7; 89 0 2 10.7; 90 0.975 2 10.7;
91 1.45 2 10.7; 92 0 4 10.7; 93 0.975 4 10.7; 94 1.45 4 10.7; 95 0 6 10.7;
96 0.975 6 10.7; 97 1.45 6 10.7; 98 0 7.42 10.7; 99 0.975 7.42 10.7;
100 1.45 7.42 10.7; 103 0 2 12.25; 104 0.975 2 12.25; 105 1.45 2 12.25;
106 0 4 12.25; 107 0.975 4 12.25; 108 1.45 4 12.25; 109 0 6 12.25;
110 0.975 6 12.25; 111 1.45 6 12.25; 112 0 7.42 12.25; 113 0.975 7.42 12.25;
114 1.45 7.42 12.25;
MEMBER INCIDENCES
11 4 10; 12 5 11; 14 7 8; 15 8 9; 16 7 10; 17 8 11; 18 9 12; 19 10 11;
20 11 12; 21 7 13; 22 8 14; 24 10 16; 25 11 17; 27 13 14; 28 14 15; 29 13 16;
30 14 17; 31 15 18; 32 16 17; 33 17 18; 34 13 19; 35 14 20; 37 16 22; 38 17 23;
40 19 20; 41 20 21; 42 19 22; 43 20 23; 44 21 24; 45 22 23; 46 23 24; 47 19 25;
48 20 26; 50 22 28; 51 23 29; 53 25 26; 54 26 27; 55 25 28; 56 26 29; 57 27 30;
58 28 29; 59 29 30; 60 10 33; 61 11 34; 62 12 35; 63 16 36; 64 17 37; 65 18 38;
66 22 39; 67 23 40; 68 24 41; 69 28 42; 70 29 43; 71 30 44; 72 31 33; 73 32 34;
74 33 34; 75 34 35; 76 33 36; 77 34 37; 78 36 37; 79 37 38; 80 36 39; 81 37 40;
82 39 40; 83 40 41; 84 39 42; 85 40 43; 86 42 43; 87 43 44; 88 33 47; 89 34 48;
90 35 49; 91 36 50; 92 37 51; 93 38 52; 94 39 53; 95 40 54; 96 41 55; 97 42 56;
98 43 57; 99 44 58; 100 45 47; 101 46 48; 102 47 48; 103 48 49; 104 47 50;
105 48 51; 106 50 51; 107 51 52; 108 50 53; 109 51 54; 110 53 54; 111 54 55;
112 53 56; 113 54 57; 114 56 57; 115 57 58; 116 47 61; 117 48 62; 118 49 63;
119 50 64; 120 51 65; 121 52 66; 122 53 67; 123 54 68; 124 55 69; 125 56 70;
126 57 71; 127 58 72; 128 59 61; 129 60 62; 130 61 62; 131 62 63; 132 61 64;
133 62 65; 134 64 65; 135 65 66; 136 64 67; 137 65 68; 138 67 68; 139 68 69;
140 67 70; 141 68 71; 142 70 71; 143 71 72; 144 61 75; 145 62 76; 146 63 77;
147 64 78; 148 65 79; 149 66 80; 150 67 81; 151 68 82; 152 69 83; 153 70 84;
154 71 85; 155 72 86; 156 73 75; 157 74 76; 158 75 76; 159 76 77; 160 75 78;
161 76 79; 162 78 79; 163 79 80; 164 78 81; 165 79 82; 166 81 82; 167 82 83;
168 81 84; 169 82 85; 170 84 85; 171 85 86; 172 75 89; 173 76 90; 174 77 91;
175 78 92; 176 79 93; 177 80 94; 178 81 95; 179 82 96; 180 83 97; 181 84 98;
182 85 99; 183 86 100; 184 87 89; 185 88 90; 186 89 90; 187 90 91; 188 89 92;
189 90 93; 190 92 93; 191 93 94; 192 92 95; 193 93 96; 194 95 96; 195 96 97;
196 95 98; 197 96 99; 198 98 99; 199 99 100; 200 89 103; 201 90 104;
202 91 105; 203 92 106; 204 93 107; 205 94 108; 206 95 109; 207 96 110;
208 97 111; 209 98 112; 210 99 113; 211 100 114; 214 103 104; 215 104 105;
216 103 106; 217 104 107; 218 106 107; 219 107 108; 220 106 109; 221 107 110;
222 109 110; 223 110 111; 224 109 112; 225 110 113; 226 112 113; 227 113 114;
228 4 33; 229 31 10; 230 10 36; 231 36 22; 232 22 42; 233 33 16; 234 16 39;
235 39 28; 236 73 89; 237 87 75; 238 75 92; 239 89 78; 240 78 95; 241 92 81;
242 81 98; 243 95 84; 244 5 34; 245 32 11; 246 11 37; 247 37 23; 248 23 43;
249 34 17; 250 17 40; 251 40 29; 252 74 90; 253 90 79; 254 79 96; 255 96 85;
256 88 76; 257 76 93; 258 93 82; 259 82 99; 260 28 43; 261 29 42; 262 84 99;
263 85 98; 264 5 10; 265 10 17; 266 17 22; 267 22 29; 268 4 11; 269 11 16;
270 16 23; 271 23 28; 272 32 33; 273 33 37; 274 37 39; 275 39 43; 276 31 34;
277 34 36; 278 36 40; 279 40 42; 280 45 48; 281 48 50; 282 50 54; 283 54 56;
284 46 47; 285 47 51; 286 51 53; 287 53 57; 288 87 90; 289 90 92; 290 92 96;
291 96 98; 292 88 89; 293 89 93; 294 93 95; 295 95 99; 296 59 62; 297 62 64;
298 64 68; 299 68 70; 300 60 61; 301 61 65; 302 65 67; 303 67 71; 304 74 75;
305 75 79; 306 73 76; 307 76 78; 308 78 82; 309 79 81; 310 81 85; 311 82 84;
312 25 29; 313 42 57; 314 57 70; 315 70 85; 316 98 113;
DEFINE MATERIAL START
ISOTROPIC MATERIAL1
E 2.05e+008
POISSON 0.3
DENSITY 77
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
CONSTANTS
MATERIAL STEEL ALL
MEMBER PROPERTY EUROPEAN
228 TO 316 TABLE ST 60.3X4CHS
11 12 14 TO 22 24 25 27 TO 35 37 38 40 TO 48 50 51 53 TO 211 214 TO 226 -
227 TABLE ST 60x4SHS
SUPPORTS
4 5 7 8 13 14 19 20 25 26 31 32 45 46 59 60 73 74 87 88 103 104 106 107 109 -
110 112 113 FIXED
MEMBER RELEASE
16 TO 18 29 TO 31 42 TO 44 55 TO 57 60 TO 71 88 TO 99 116 TO 127 144 TO 155 -
172 TO 183 200 TO 211 228 TO 316 START MZ
16 TO 18 29 TO 31 42 TO 44 55 TO 57 60 TO 71 88 TO 99 116 TO 127 144 TO 155 -
172 TO 183 200 TO 211 228 TO 316 END MZ
LOAD 1 LOADTYPE None TITLE EQ X +
PERFORM ANALYSIS
CHANGE
LOAD 2 LOADTYPE None TITLE EQ X -
PERFORM ANALYSIS
CHANGE
LOAD 3 LOADTYPE None TITLE DL
SELFWEIGHT Y -1
ONEWAY LOAD
YRANGE 2 7.42 ONE -1 GY
LOAD 4 LOADTYPE None TITLE LL
ONEWAY LOAD
YRANGE 2 7.42 ONE -0.5 GY
LOAD 5 LOADTYPE None TITLE CL
ONEWAY LOAD
YRANGE 2 7.42 ONE -0.2 GY
LOAD 6 LOADTYPE None TITLE WL LEFT
MEMBER LOAD
11 21 24 34 37 47 50 53 72 76 80 84 100 104 108 112 128 132 136 140 156 160 -
164 168 184 188 192 196 216 220 224 UNI GX 4.6
53 54 58 59 86 87 114 115 142 143 170 171 198 199 226 227 UNI Y 3.54
12 22 25 35 38 48 51 73 77 81 85 101 105 109 113 129 133 137 141 157 161 165 -
169 185 189 193 197 217 221 225 UNI GX 4.6
LOAD 7 LOADTYPE None TITLE WL RIGHT
MEMBER LOAD
11 21 24 34 37 47 50 53 72 76 80 84 100 104 108 112 128 132 136 140 156 160 -
164 168 184 188 192 196 216 220 224 UNI GX -4.6
53 54 58 59 86 87 114 115 142 143 170 171 198 199 226 227 UNI Y 3.54
12 22 25 35 38 48 51 73 77 81 85 101 105 109 113 129 133 137 141 157 161 165 -
169 185 189 193 197 217 221 225 UNI GX -4.6
LOAD 8 LOADTYPE None TITLE WL END
MEMBER LOAD
11 21 24 34 37 47 50 53 72 76 80 84 100 104 108 112 128 132 136 140 156 160 -
164 168 184 188 192 196 216 220 224 UNI GX -4.6
53 54 58 59 86 87 114 115 142 143 170 171 198 199 226 227 UNI Y 3.54
12 22 25 35 38 48 51 73 77 81 85 101 105 109 113 129 133 137 141 157 161 165 -
169 185 189 193 197 217 221 225 UNI GX 4.6
LOAD COMB 100 1.4DL
1 1.4
LOAD COMB 101 1.2DL + 0.5LL + 1.2CL
1 1.2 2 0.5 3 1.2
LOAD COMB 102 1.2DL + 1.6LL + 1.2CL
1 1.2 2 1.6 3 1.2
LOAD COMB 103 1.2DL + 1.6LL + 0.8WL LEFT
1 1.2 2 1.6 4 0.8
LOAD COMB 104 1.2DL + 1.6LL + 0.8WL RIGHT
1 1.2 2 1.6 5 0.8
LOAD COMB 105 1.2DL + 1.6LL + 0.8WL END
1 1.2 2 1.6 6 0.8
LOAD COMB 106 1.2DL + 0.5LL + 1.6WL LEFT
1 1.2 2 0.5 4 1.6
LOAD COMB 107 1.2DL + 0.5LL + 1.6WL RIGHT
1 1.2 2 0.5 5 1.6
LOAD COMB 108 1.2DL + 0.5LL + 1.6WL END
1 1.2 2 0.5 6 1.6
LOAD COMB 109 0.9DL + 1.6WL LEFT
1 0.9 4 1.6
LOAD COMB 110 0.9DL + 1.6WL RIGHT
1 0.9 5 1.6
LOAD COMB 111 0.9DL + 1.6WL END
1 0.9 6 1.6
LOAD COMB 112 1.2DL + LL + EQ+
3 1.2 1 1.0 4 1.0
LOAD COMB 113 1.2DL + LL + EQ-
3 1.2 4 1.0 2 1.0
LOAD COMB 114 0.9DL + EQ+
3 0.9 1 1.0
LOAD COMB 115 0.9DL + EQ-
3 0.9 2 1.0
LOAD COMB 200 DL + CL + LL
1 1.0 2 1.0 3 1.0
LOAD COMB 201 DL + 0.75WL LEFT
1 1.0 4 0.75
LOAD COMB 202 DL + 0.75WL RIGHT
1 1.0 5 0.75
LOAD COMB 203 DL + 0.75WL END
1 1.0 6 0.75
PERFORM ANALYSIS
LOAD LIST 100 TO 115
PARAMETER 1
CODE LRFD
FYLD 345000 ALL
CHECK CODE ALL
STEEL TAKE OFF ALL
FINISH

 

[Ingenuity]

...and you expect one of us to run the file and find the member that fails!

How about providing a sketch of the roof structure?

Have you done a simplified hand calculation of the member in question?

 

[klaus.]

probably there is a numerical instability...
check the node or member and fix it by a (soft)spring
If it is torsional sometimes a beam member can rotate around the longitudinal axis if it is attached to pin ended members only...

 

[WARose]

Which member are we talking? I ran it myself on STAAD (using a code I am more familiar with: AISC 13^th edition, LRFD) and I am getting 3 members failing. The one at the roof: member 316. And it isn't failing because of torsion (in has no significant amount in it)......it is failing because of axial compression.

It's been a while since I've run STAAD with LRFD 3rd. (In fact, I've rarely run it with that code at all. That's one code I just about completely missed.) But the few times I have run it, I think it is just calling it that (in the output) because it is a combination that includes a torsion utilization ratio......even if it is not a significant level of it. (That's my guess anyway.)

 

[271828]

From the title, I thought a member failed in a real roof! LOL

 

[JAE]

Is there anything in your input that defines unbraced lengths of members? That is many times a problem in computer analysis/design runs where the user will enter the geometry, loads, releases, load combinations, etc. and then find members failing everywhere - only to realize that they skipped over one of the most important inputs - defining if and how the members are laterally braced.

Check out Eng-Tips Forum's Policies here:
faq731-376

 

[WARose]

[blue](JAE)[/blue]

Is there anything in your input that defines unbraced lengths of members?

That's a good point I forgot to mention: the unbraced lengths are not defined. Although in the case I mentioned, I doubt it is braced by anything because it is a pipe cross section (acting as plan bracing). It's rare to have top of steel of a section like that at a elevation where anything (i.e. deck, etc) could attach to it to brace it.

 

[JAE]

...and proper K value definitions unless a Direct Design method is used with all K's = 1.0.

Check out Eng-Tips Forum's Policies here:
faq731-376

 

[WARose]

...and proper K value definitions unless a Direct Design method is used with all K's = 1.0.

Yep. STADD defaults to "1". This thing appears to be braced so it may not be needed.....but it's worth pointing out.

I also use the BEAM 1 ALL command so that STAAD checks it at multiple locations along the span (13 with that command). It may default to that at this point.....but I am a old school user so I call it out anyway.

 

[Archie264]

I haven't run the model and don't know what the structure even looks like but I always check to see how many supports are modeled as fixed. In this case it appears that three of them are. (SUPPORTS...110 112 113 FIXED). My question is, are they really fixed? And if so, what has been done to build them that way? Support fixity can really affect the model so if it's not to be achieved in reality...well, be careful.

{Edit} Whoops, I misread the file. It looks like all the supports are fixed.