Sir,
We have a steel structure supporting the snubber ( sketch attached). Snubber self-weight & snubber load in OBE and SSE condition is available.
Clarification point :In the seismic load case, we define the masses in loads.Self-weight of the structure, snubber self-weight & snubber OBE & SSE loads are defined in all three directions(x,y &Z). Model details are attached, and the qualification is done.
Doubt is:Self-weight of the structure and the snubber self-weight are permanent weights, and it is clear that we have to define them in all three directions.But the OBE & SSE snubber load are generated in seismic conditions in a particular direction, whether this load is also to be considered in three directions in the seismic load case.Kindly clarify at the earliest.
STAAD SPACE START JOB INFORMATION ENGINEER DATE 20-Jul-21 END JOB INFORMATION INPUT WIDTH 79 UNIT MMS NEWTON JOINT COORDINATES 1 0 1 0; 2 0 4000 0; 3 0 3300 0; MEMBER INCIDENCES 1 1 3; 2 3 2; DEFINE MATERIAL START ISOTROPIC STEEL E 205000 POISSON 0.3 DENSITY 7.68195e-005 ALPHA 1.2e-005 DAMP 0.03 TYPE STEEL STRENGTH FY 253.2 FU 407.8 RY 1.5 RT 1.2 ISOTROPIC RIGID E 2e+010 POISSON 0.3 END DEFINE MATERIAL MEMBER PROPERTY INDIAN 1 2 TABLE FR ISMC150 CONSTANTS MATERIAL STEEL ALL SUPPORTS 1 FIXED LOAD 1 LOADTYPE Dead TITLE DL SELFWEIGHT Y -1 JOINT LOAD 3 FY -60 LOAD 3 LOADTYPE Live TITLE SL(SSE) JOINT LOAD 3 FX 315 LOAD 5 LOADTYPE Live TITLE SL(SSE)WITH -VE JOINT LOAD 3 FX -315 LOAD 9 LOADTYPE Seismic TITLE EQX(SSE) SELFWEIGHT X 1 SELFWEIGHT Y 1 SELFWEIGHT Z 1 JOINT LOAD 3 FX 315 3 FY 315 3 FZ 315 3 FX 60 3 FY 60 3 FZ 60 SPECTRUM SRSS X 1 ACC DAMP 0 LIN MIS 0 20 1207.1; 4 1207.1; 2.85714 1472.4; 2.5 1663.4; 2.22222 2032.6; 2 2269.8; 1.53846 2648.4; 1.42857 2949.5; 1.25 3232.2; 1.17647 3546.9; 1.05263 3828.5; 1 3885; 0.909091 3885; 0.833333 4009.6; 0.8 4393.7; 0.689655 4646; 0.666667 5076.5; 0.645161 5932.7; 0.625 6358.2; 0.588235 6756; 0.555556 8034.9; 0.540541 9313.7; 0.487805 11347.7; 0.47619 12944.1; 0.454545 14540.6; 0.425532 19580.2; 0.416667 23646.3; 0.4 28418.6; 0.294118 28418.6; 0.273973 24372.9; 0.27027 23840.5; 0.263158 21763; 0.25974 20750.3; 0.25641 19789.8; 0.253165 18933.5; 0.25 18285.9; 0.246914 18055.3; 0.243902 17594.3; 0.229885 11245.8; 0.224719 10283; 0.217391 9599.3; 0.212766 9778.6; 0.206186 11773.3; 0.204082 12340.9; 0.20202 13454.6; 0.19802 14546.8; 0.192308 15079.5; 0.190476 16510.6; 0.188679 17226.2; 0.185185 17853.7; 0.18018 18651; 0.134228 18651; 0.130719 18516.6; 0.128205 18516.6; 0.126582 18073.1; 0.125 17359.5; 0.124224 17089.5; 0.123457 16901.9; 0.122699 16879.2; 0.0943396 16879.2; 0.0938967 16762.4; 0.0930233 16634.8; 0.0925926 16617; 0.0921659 16531.7; 0.0913242 16446.4; 0.0909091 16361.1; 0.0896861 15673.6; 0.0892857 15254.3; 0.0884956 15111; 0.0823045 15111; 0.0809717 14848.9; 0.0803213 13601.5; 0.08 13511.1; 0.0796813 13330.4; 0.0793651 12985.4; 0.078125 12199.4; 0.0775194 11953.8; 0.0772201 11708.2; 0.0766283 11149; 0.0760456 10888; 0.0740741 10482.5; 0.0738007 10233.2; 0.0727273 9774.2; 0.0724638 9643.6; 0.0716846 9481.7; 0.0704225 9339.4; 0.0701754 9184.8; 0.0687285 9065.5; 0.0682594 8670.1; 0.0680272 8516.9; 0.0677966 8452.5; 0.0671141 8405.4; 0.0591716 8405.4; 0.0588235 8204.9; 0.0584795 8104.7; 0.0554017 7879.7; 0.0550964 7656.7; 0.0547945 7545.1; 0.0546448 7433.6; 0.0533333 7393.4; 0.0508906 7393.4; 0.0496278 7168.6; 0.0492611 6839.6; 0.0488998 6637; 0.0486618 6569.5; 0.0483092 6268.9; 0.0465116 6027.9; 0.0462963 5921.3; 0.0460829 5868.1; 0.0458716 5761.5; 0.045045 5704.8; 0.0378072 5704.8; 0.030303 5557; LOAD 10 LOADTYPE Seismic TITLE EQY(SSE) SPECTRUM SRSS Y 0.67 ACC DAMP 0 LIN MIS 0 20 811.8; 4 811.8; 2.85714 961.7; 2.5 1091.6; 2.22222 1330.2; 2 1485.4; 1.53846 1710.3; 1.42857 1992; 1.25 2054.5; 1.17647 2208.2; 1.05263 2397.5; 1 2402.7; 0.869565 2402.7; 0.740741 2762.7; 0.714286 2762.7; 0.666667 2819.2; 0.645161 3167.3; 0.625 3319; 0.606061 3319; 0.571429 3372.1; 0.555556 3510.8; 0.540541 3788.2; 0.487805 4742.7; 0.47619 5190.5; 0.454545 5638.4; 0.425532 7114.4; 0.416667 8614.1; 0.4 10629.5; 0.289855 11016.4; 0.285714 11438.4; 0.28169 12282.4; 0.273973 13126.4; 0.263158 14701.2; 0.25974 15114.6; 0.253165 15528; 0.246914 15857.8; 0.243902 16179.3; 0.238095 16500.8; 0.232558 16928.6; 0.229885 17466.3; 0.227273 18342.1; 0.224719 18680.1; 0.217391 22913.4; 0.215054 24116; 0.212766 26278; 0.206186 30451.5; 0.204082 32528.5; 0.20202 35825.4; 0.19802 38265.1; 0.194175 38265.1; 0.190476 38987.2; 0.188679 39449.8; 0.185185 40499.2; 0.181818 42470; 0.18018 43997.6; 0.178571 44539.8; 0.175439 44630.5; 0.12987 44630.5; 0.128205 43724.5; 0.126582 42156.4; 0.125786 40588.2; 0.124224 36766.8; 0.123457 35007.2; 0.122699 33549.8; 0.121951 32234.5; 0.121212 31203; 0.120482 30515.4; 0.119048 27701.5; 0.116959 26373; 0.116279 25974.4; 0.115607 25634.8; 0.111732 24443.5; 0.111111 24294.8; 0.110497 24195.7; 0.10929 23271.3; 0.108108 21696.9; 0.107527 21040.8; 0.106952 20660.6; 0.106383 20301.8; 0.10582 19985.7; 0.105263 19755.3; 0.104712 19696.1; 0.0787402 19696.1; 0.078125 19482; 0.0775194 19160.4; 0.0772201 18838.7; 0.0766283 18028.7; 0.0760456 16980.3; 0.0757576 16539.5; 0.0754717 16265.3; 0.075188 16020.7; 0.0740741 15279.1; 0.0738007 15065.8; 0.0732601 14852.5; 0.0727273 14593.5; 0.0724638 14430; 0.0716846 14111; 0.0711744 13996.9; 0.0704225 13637.7; 0.0701754 13446.1; 0.0687285 13357.4; 0.0682594 13042.1; 0.0680272 12935.1; 0.0657895 12563; 0.0649351 11495.4; 0.0645161 11354.5; 0.0641026 11284.1; 0.0630915 10765.4; 0.0626959 10652.8; 0.0591716 10209.2; 0.0588235 9018.7; 0.058651 8732.2; 0.058309 8445.7; 0.0554017 8445.7; 0.0526316 8197.3; 0.0520833 7998.1; 0.0496278 7858; 0.0465116 7693.1; 0.030303 7106.5; LOAD 11 LOADTYPE Seismic TITLE EQZ(SSE) SPECTRUM SRSS Z 1 ACC DAMP 0 LIN MIS 0 20 1208.3; 4 1208.3; 2.85714 1438.1; 2.5 1634.3; 2.22222 1980.6; 2 2223.8; 1.66667 2409.3; 1.53846 2591.9; 1.42857 2943.8; 1.25 3055.2; 1.17647 3395.8; 1.05263 3596.8; 0.909091 3596.8; 0.833333 3756; 0.8 3991.8; 0.740741 4332; 0.714286 4332; 0.666667 4576.9; 0.645161 4987.5; 0.625 5148.6; 0.588235 5401.9; 0.555556 5965; 0.540541 6528; 0.487805 8554; 0.47619 8888.8; 0.454545 9223.6; 0.425532 11220.8; 0.416667 12701.2; 0.4 14330.6; 0.377358 14499.3; 0.28169 14499.3; 0.273973 14081; 0.27027 13941.6; 0.25641 12878.5; 0.253165 12652.1; 0.25 12478.2; 0.246914 12409.3; 0.243902 12271.3; 0.240964 11726.8; 0.235294 11243.9; 0.232558 11243.9; 0.224719 11351.2; 0.204082 11351.2; 0.2 11357.2; 0.19802 11770.6; 0.192308 12471.4; 0.190476 13095.2; 0.188679 13407.1; 0.185185 13517.3; 0.181818 14049.9; 0.18018 14457.4; 0.178571 14598.6; 0.13245 14855; 0.131579 15493.3; 0.12987 16657.9; 0.129032 17085.5; 0.128205 17940.7; 0.127389 18100.2; 0.125786 18308.6; 0.125 18353.3; 0.0925926 18353.3; 0.0917431 18083.7; 0.0913242 17993.8; 0.0904977 17752.8; 0.0900901 17691.6; 0.0896861 17650.8; 0.0823045 17650.8; 0.0809717 17531; 0.0806452 16588.6; 0.08 16444.6; 0.0796813 16300.7; 0.0793651 15704.1; 0.078125 14790.1; 0.0775194 14479.7; 0.0766283 13554.5; 0.0760456 13135.5; 0.0754717 12926; 0.0743494 12378.6; 0.0738007 12246.1; 0.0704225 12246.1; 0.0687285 12167.8; 0.0680272 11980.6; 0.0675676 11918; 0.0657895 11845.9; 0.0645161 10435; 0.0634921 9864.5; 0.0591716 9640.8; 0.0588235 8745; 0.0584795 8297.1; 0.0574713 7918.4; 0.0571429 7856.3; 0.0568182 7732; 0.0554017 7575.2; 0.0550964 7450.2; 0.0547945 7387.7; 0.0546448 7325.2; 0.0526316 7152.5; 0.0522193 6589.9; 0.0508906 6493.5; 0.0507614 6394.3; 0.050505 6295.1; 0.0503778 6195.9; 0.0496278 6050.4; 0.0492611 5874; 0.0486618 5810.1; 0.0483092 5692.8; 0.0465116 5601.2; 0.0462963 5442; 0.0460829 5362.3; 0.0458716 5203.1; 0.04329 4861.2; 0.030303 4175.2; LOAD COMB 16 LC5(SSE) 1 1.0 3 1.0 9 1.0 LOAD COMB 17 LC6(SSE) 1 1.0 3 1.0 10 1.0 LOAD COMB 18 LC7(SSE) 1 1.0 3 1.0 11 1.0 LOAD COMB SRSS 19 LC8(SSE) -1 1.0 -3 1.0 9 1.0 10 1.0 11 1.0 1 LOAD COMB 24 LC24(SSE WITH -VE SL) 1 1.0 5 1.0 9 1.0 LOAD COMB 25 LC25(SSE WITH -VE SL) 1 1.0 5 1.0 10 1.0 LOAD COMB 26 LC26(SSE WITH -VE SL) 1 1.0 5 1.0 11 1.0 LOAD COMB SRSS 27 LC27(SSE WITH -VE SL) -1 1.0 -5 1.0 9 1.0 10 1.0 11 1.0 1 PERFORM ANALYSIS PRINT STATICS CHECK FINISH
Can some help on this clarification
Can you please explain how OBE & SSE snubber load are generated in seismic conditions ? Ideally, seismic loads are inertial forces and generated for gravity loads.
s ,OBE & SSE snubber load are the inertia forces generated from the piping systems. If this is inertial load, whether my analysis with the OBE & SSE snubber load defined in all three direction as mass for the seismic load is correct??
Back ground is one end snubber is connected to the piping and other end is connected to steel structure.
The snubber loads are generated from the piping analysis done in OBE and SSE conditions.basically it is the restraint reaction loads of piping in OBE and SSE condition
Kindly clarify
As these loads are related to inertia forces, they should be considered in mass modelling used to form mass matrix in the seismic analysis
Answer Verified By: nir
thank you