Sir,
The steel structure model is checked for seismic loads with the site specific spectra . I am checking the qualification of structure w.r.t to stresses and deflection .
Clarification :
Whether i need to check the natural frequency of structure (I have attached the Site spectra used for analysis).
STAAD SPACE START JOB INFORMATION ENGINEER DATE 11-Nov-21 END JOB INFORMATION INPUT WIDTH 79 UNIT MMS NEWTON JOINT COORDINATES 1 0 0 0; 2 0 1160 0; 3 0 175 0; 4 0 175 785; 5 0 175 375; 6 640 175 375; 7 520 175 375; 9 520 -110 375; 10 260 175 375; 11 0 675 0; MEMBER INCIDENCES 1 1 3; 2 3 11; 3 3 5; 4 5 4; 5 5 10; 6 7 6; 7 7 9; 8 10 7; 9 10 3; 12 11 2; 13 11 5; 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 END DEFINE MATERIAL MEMBER PROPERTY INDIAN 1 TO 8 12 13 TABLE FR ISMC150 9 TABLE FR ISMC100 CONSTANTS MATERIAL STEEL ALL SUPPORTS 2 FIXED LOAD 1 LOADTYPE Dead TITLE DL SELFWEIGHT Y -1 JOINT LOAD 9 FY -150 LOAD 3 LOADTYPE Live TITLE SL(SSE) JOINT LOAD 9 FY 1418 LOAD 5 LOADTYPE Live TITLE SL(SSE)WITH -VE JOINT LOAD 9 FY -1418 LOAD 9 LOADTYPE Seismic TITLE EQX(SSE) SELFWEIGHT X 1 SELFWEIGHT Y 1 SELFWEIGHT Z 1 SPECTRUM SRSS X 1 ACC DAMP 0 LIN MIS 0 20 1193.6; 4 1193.6; 2.85714 1422.3; 2.5 1617.9; 2.22222 1945.8; 2 2181; 1.66667 2367.2; 1.53846 2513.4; 1.42857 2807.3; 1.25 2962.9; 1.17647 3193.4; 1.05263 3375.2; 0.869565 3375.2; 0.8 3487.7; 0.740741 3788.5; 0.714286 3788.5; 0.666667 3937.6; 0.645161 4265.7; 0.625 4432; 0.588235 4446.4; 0.555556 4674; 0.540541 4901.6; 0.487805 5927.8; 0.465116 5927.8; 0.444444 6193.5; 0.425532 6893.2; 0.416667 7599.6; 0.4 8312.6; 0.294118 8312.6; 0.285714 7493.5; 0.28169 7185.4; 0.232558 6855; 0.227273 7209.7; 0.212766 7242.9; 0.206186 7611.2; 0.20202 7701.7; 0.19802 7727.5; 0.192308 7938.9; 0.190476 8289.1; 0.185185 8800.3; 0.181818 9054.8; 0.18018 9208.7; 0.178571 9235.4; 0.131579 9235.4; 0.12987 9145.6; 0.128205 8932.1; 0.127389 8875.1; 0.125786 9058.5; 0.125 9090.6; 0.0925926 9090.6; 0.0909091 8988.7; 0.0892857 8742; 0.0877193 8677.2; 0.0869565 8552.8; 0.0865801 8520; 0.0858369 8310.4; 0.0854701 8226.8; 0.0851064 8185.5; 0.0840336 7979.7; 0.08 8028.7; 0.0591716 8028.7; 0.0588235 7505.1; 0.058651 7287.5; 0.0584795 7158.5; 0.058309 7053.6; 0.0571429 6723.1; 0.0560224 6460.8; 0.0554017 6298.8; 0.0550964 5902.6; 0.0549451 5732.7; 0.0544959 5376; 0.0526316 5184.1; 0.052356 4879.1; 0.0522193 4747.8; 0.0520833 4659.1; 0.0508906 4627; 0.0502513 4422.2; 0.0496278 4354.4; 0.0486618 4065.1; 0.0465116 3813.5; 0.0433839 3274.8; 0.04329 3216.5; 0.0357782 2795.6; 0.0322061 2795.6; 0.030303 2624; LOAD 10 LOADTYPE Seismic TITLE EQY(SSE) SPECTRUM SRSS Y 0.67 ACC DAMP 0 LIN MIS 0 20 797.5; 4 797.5; 2.85714 948.8; 2.5 1078.2; 2.22222 1291.6; 2 1444.2; 1.66667 1568.4; 1.53846 1666.5; 1.42857 1878.8; 1.25 1960.3; 1.17647 2118.6; 1.05263 2272.7; 0.869565 2272.7; 0.8 2331.9; 0.769231 2391.1; 0.740741 2521.8; 0.714286 2521.8; 0.666667 2542; 0.645161 2744.7; 0.625 2849.3; 0.588235 2849.8; 0.555556 2969.2; 0.540541 3088.5; 0.487805 4043.3; 0.47619 4256.4; 0.454545 4469.6; 0.425532 4903.1; 0.416667 5521.8; 0.4 6470.3; 0.294118 6470.3; 0.28169 6284.8; 0.25974 6950; 0.253165 7038.8; 0.243902 7282.6; 0.238095 7376.2; 0.212766 7501.6; 0.206186 7857.8; 0.204082 8091.4; 0.20202 8550.9; 0.19802 9002.4; 0.145985 9002.4; 0.133333 8867.3; 0.131579 9460.2; 0.12987 9611.8; 0.129032 9799.2; 0.128205 10173.9; 0.127389 10190.2; 0.0938967 10190.2; 0.0930233 10112.9; 0.0913242 9828.1; 0.0843882 8609; 0.0833333 8477.5; 0.0826446 8455; 0.0809717 8455; 0.0803213 8173.3; 0.08 8148; 0.0796813 8097.4; 0.0790514 7849.2; 0.077821 7437.3; 0.0775194 7371.8; 0.0763359 6818; 0.0757576 6617.4; 0.0740741 6156.8; 0.0735294 5836; 0.0732601 5704.6; 0.0729927 5630.8; 0.0727273 5589.3; 0.0719424 5581.4; 0.0711744 5581.4; 0.0696864 5485; 0.0687285 5485; 0.0682594 5389.3; 0.0657895 5365.9; 0.0641026 4983.8; 0.0591716 4610.1; 0.058651 4104.1; 0.0584795 3988.1; 0.058309 3917.2; 0.0581395 3868; 0.0555556 3627; 0.0546448 3627; 0.0508906 3583.2; 0.0501253 3458.5; 0.0496278 3458.5; 0.0493827 3457.7; 0.0486618 3457.7; 0.0465116 3421.6; 0.0462963 3340.2; 0.0460829 3299.4; 0.0458716 3218; 0.0452489 3147.9; 0.0433839 2743; 0.04329 2659.8; 0.030303 2265.9; LOAD 11 LOADTYPE Seismic TITLE EQZ(SSE) SPECTRUM SRSS Z 1 ACC DAMP 0 LIN MIS 0 20 1197.4; 4 1197.4; 2.85714 1423.8; 2.5 1619.7; 2.22222 1946.8; 2 2184.5; 1.66667 2362; 1.53846 2514.6; 1.42857 2839.1; 1.25 2964.9; 1.17647 3207.6; 1.05263 3414.1; 0.869565 3414.1; 0.8 3536.9; 0.740741 3861.6; 0.714286 3861.6; 0.666667 3972; 0.645161 4218; 0.625 4315.9; 0.588235 4387.7; 0.555556 4637.7; 0.540541 4887.6; 0.487805 5969; 0.454545 6031.5; 0.425532 7171.6; 0.416667 7883.4; 0.4 8547.1; 0.377358 8579.8; 0.28169 8579.8; 0.277778 8469.1; 0.266667 8320.4; 0.263158 8308.6; 0.25974 8369; 0.253165 8429.4; 0.204082 8432.1; 0.20202 8597.5; 0.19802 8741.4; 0.192308 8865; 0.190476 9090.3; 0.188679 9202.9; 0.185185 9304.4; 0.181818 9447.1; 0.18018 9574.7; 0.178571 9631.1; 0.148148 9698.9; 0.147059 9843.6; 0.145985 9900.4; 0.137931 9900.4; 0.136054 9960.5; 0.134228 10365; 0.133333 10603.1; 0.131579 10841.2; 0.129032 11614.9; 0.128205 12104.5; 0.127389 12144.8; 0.125786 12524.2; 0.0930233 12524.2; 0.0925926 12504.7; 0.0917431 12308; 0.0913242 12242.4; 0.0884956 11456.5; 0.0881057 11387.2; 0.0865801 11304.8; 0.0809717 11304.8; 0.0803213 11108.6; 0.08 11059.9; 0.0796813 10962.5; 0.0790514 10579.6; 0.0784314 10257; 0.077821 10010.4; 0.0775194 9921.8; 0.0760456 8986; 0.0757576 8828.6; 0.075188 8656.3; 0.0740741 8472.3; 0.0735294 8142.3; 0.0724638 7722.4; 0.0722022 7647.7; 0.0714286 7529.3; 0.0706714 7523.2; 0.0701754 7523.2; 0.0687285 7514.2; 0.0684932 7410.9; 0.0680272 7311.7; 0.0675676 7311.7; 0.0657895 7259.1; 0.0643087 6630.1; 0.0641026 6575.8; 0.0628931 6131.9; 0.0591716 5937.6; 0.0588235 5312.7; 0.058651 5055.7; 0.0584795 4909.6; 0.058309 4801.3; 0.0554017 4377.1; 0.0544959 4115.3; 0.0526316 4036.5; 0.0520833 3866.1; 0.0508906 3847.4; 0.0502513 3682.8; 0.0433839 3196.9; 0.0431965 3144.1; 0.030303 2692.3; LOAD COMB 20 LC1(SSE) 1 1.0 9 1.0 3 1.0 LOAD COMB 21 LC2(SSE) 1 1.0 10 1.0 3 1.0 LOAD COMB 22 LC3(SSE) 1 1.0 11 1.0 3 1.0 LOAD COMB SRSS 23 LC4(SSE) -1 1.0 9 1.0 10 1.0 11 1.0 -3 1.0 1 LOAD COMB 24 LC1(SSE WITH -VE SL) 1 1.0 5 1.0 9 1.0 LOAD COMB 25 LC2(SSE WITH -VE SL) 1 1.0 5 1.0 10 1.0 LOAD COMB 26 LC3(SSE WITH -VE SL) 1 1.0 5 1.0 11 1.0 LOAD COMB SRSS 27 LC4(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 LOAD 1 LOADTYPE Dead TITLE DL SELFWEIGHT Y -1 JOINT LOAD 8 FY -150 LOAD 2 LOADTYPE Live TITLE SL(OBE) JOINT LOAD 8 FY 896 LOAD 4 LOADTYPE Live TITLE SL(OBE)WITH -VE JOINT LOAD 8 FY -896 LOAD 6 LOADTYPE Seismic TITLE EQX(OBE) SELFWEIGHT X 1 SELFWEIGHT Y 1 SELFWEIGHT Z 1 JOINT LOAD 8 FX 896 8 FY 896 8 FZ 896 8 FX 150 8 FY 150 8 FZ 150 SPECTRUM SRSS X 0.5 ACC DAMP 0 LIN MIS 0 20 642.3; 4 642.3; 2.5 971.4; 2.22222 1238.5; 2 1386.7; 1.53846 1541.9; 1.42857 1771.8; 1.33333 1771.8; 1.17647 2049.3; 1.05263 2206.9; 0.869565 2206.9; 0.740741 2506.9; 0.714286 2506.9; 0.666667 2588.5; 0.645161 2815.4; 0.625 2885.7; 0.588235 2885.7; 0.555556 3033.9; 0.540541 3445; 0.487805 3714.5; 0.47619 3901; 0.454545 4087.5; 0.425532 5008.1; 0.416667 6094.3; 0.4 7652.8; 0.294118 7652.8; 0.285714 6305; 0.28169 5719.4; 0.277778 5310.2; 0.27027 5216.6; 0.253165 4842.1; 0.240964 4804.6; 0.238095 4902; 0.208333 4931.3; 0.204082 5025.4; 0.20202 5230.2; 0.19802 5552.7; 0.192308 5730.5; 0.190476 6146.6; 0.188679 6354.7; 0.18018 6391.1; 0.134228 6391.1; 0.131579 6373.2; 0.12987 6542.8; 0.0961538 6542.8; 0.0952381 6449.7; 0.0930233 6405.7; 0.0925926 6375.4; 0.0921659 6264.3; 0.0909091 6101.6; 0.0904977 6094.9; 0.0896861 6309.2; 0.0892857 6523.5; 0.0877193 6768.9; 0.0873362 6768.9; 0.0865801 6789.3; 0.0858369 6976.8; 0.0851064 6979.5; 0.0626959 6979.5; 0.0591716 6911.2; 0.0588235 5887.8; 0.058651 5697.3; 0.058309 5506.9; 0.0568182 5506.9; 0.0554017 5261.7; 0.0550964 4632.1; 0.0549451 4362.3; 0.0544959 3794.6; 0.0526316 3480.7; 0.052356 3112.7; 0.0522193 2954.4; 0.0520833 2847.5; 0.0508906 2812.8; 0.0502513 2574.9; 0.0496278 2528.1; 0.0452489 2106.7; 0.0433839 1876.6; 0.04329 1835.8; 0.0357143 1592.4; 0.0322061 1592.4; 0.030303 1473.8; LOAD 7 LOADTYPE Seismic TITLE EQY(OBE) SPECTRUM SRSS Y 0.33 ACC DAMP 0 LIN MIS 0 20 429.3; 4 429.3; 2.5 647; 2.22222 819.6; 2 919.7; 1.53846 1021.7; 1.42857 1186.2; 1.33333 1186.2; 1.17647 1361.9; 1.05263 1469.4; 1 1478.8; 0.869565 1478.8; 0.740741 1644.6; 0.714286 1644.6; 0.666667 1689.9; 0.645161 1792.2; 0.625 1800; 0.588235 1800; 0.555556 1886.2; 0.540541 2099.5; 0.487805 2492.3; 0.47619 2745.1; 0.454545 2997.9; 0.425532 3600.7; 0.416667 4470; 0.4 5806.8; 0.294118 5806.8; 0.28169 4840; 0.266667 4651.5; 0.263158 4831.2; 0.25 4935.2; 0.246914 5195.4; 0.243902 5529.4; 0.238095 5863.4; 0.212766 5863.4; 0.208333 6031.4; 0.206186 6215.2; 0.204082 6544.6; 0.20202 7150.8; 0.19802 7704.2; 0.145985 7704.2; 0.142857 7702.7; 0.141844 7564.7; 0.13986 7443.8; 0.134228 7406.6; 0.133333 8257.9; 0.12987 9924.1; 0.0961538 9924.1; 0.0930233 9815.6; 0.0921659 9590.4; 0.0917431 9501.6; 0.0913242 9460.4; 0.0909091 9439.8; 0.0809717 9439.8; 0.0803213 9359.5; 0.0796813 9336.8; 0.0790514 9162.5; 0.0787402 9104.4; 0.078125 8903; 0.0775194 8767.9; 0.0772201 8632.7; 0.0760456 7274.8; 0.0754717 6928.1; 0.0740741 6347.3; 0.0738007 5916; 0.0732601 5484.7; 0.0727273 5450.7; 0.0711744 5450.7; 0.0704225 5420; 0.0699301 5295.7; 0.0687285 5219.2; 0.0682594 4909.2; 0.0680272 4786.7; 0.0677966 4729.3; 0.0657895 4612.7; 0.0643087 4159; 0.0641026 4114.8; 0.0591716 3521.6; 0.0588235 3196.6; 0.058651 3114; 0.0465116 3114; 0.0458716 3009; 0.0452489 2706; 0.0444444 2349.8; 0.0433839 2006.9; 0.0431965 1889.9; 0.0323102 1392.9; 0.030303 1392.9; LOAD 8 LOADTYPE Seismic TITLE EQZ(OBE) SPECTRUM SRSS Z 0.5 ACC DAMP 0 LIN MIS 0 20 644.6; 4 644.6; 2.5 971.8; 2.22222 1232.1; 2 1388.6; 1.53846 1541.5; 1.42857 1786.9; 1.33333 1786.9; 1.17647 2039.4; 1.05263 2233.9; 0.869565 2233.9; 0.8 2359.3; 0.740741 2548.3; 0.714286 2548.3; 0.666667 2582.6; 0.645161 2762.9; 0.625 2821.1; 0.588235 2821.1; 0.555556 2970.2; 0.540541 3367.1; 0.47619 3885.4; 0.454545 4004.7; 0.425532 4812.9; 0.416667 5661.7; 0.4 6820.4; 0.294118 6820.4; 0.289855 6671.2; 0.285714 6570.5; 0.20202 6208.2; 0.19802 6546.1; 0.192308 6648.3; 0.190476 7168.6; 0.188679 7428.8; 0.185185 7502.7; 0.135135 7591.5; 0.134228 7904.8; 0.133333 8669.9; 0.12987 10225.3; 0.129032 10450; 0.128205 10899.4; 0.125786 10957.7; 0.0930233 10957.7; 0.0925926 10616.5; 0.0921659 10467.2; 0.0913242 10317.8; 0.0909091 10168.5; 0.0904977 9797.4; 0.0896861 9469.4; 0.0809717 9469.4; 0.0803213 9212; 0.08 9105.9; 0.0790514 8931.8; 0.0787402 8910.2; 0.078125 8787.4; 0.0775194 8620.8; 0.0772201 8454.2; 0.0763359 7597.2; 0.0760456 7343.4; 0.0757576 7124.7; 0.0754717 6950.4; 0.075188 6844.3; 0.0746269 6746.9; 0.0657895 6746.9; 0.0645161 6661; 0.0641026 6661; 0.0634921 6614.2; 0.0632911 6529.7; 0.0628931 6408.1; 0.0591716 5989.1; 0.0588235 4600.8; 0.058651 4031.7; 0.0584795 3712.6; 0.058309 3483.9; 0.0566572 3088.1; 0.0554017 3029.8; 0.0544959 2805.5; 0.0526316 2680.9; 0.0522193 2522.9; 0.0519481 2486.3; 0.0508906 2486.3; 0.0501253 2418.7; 0.0465116 2418.7; 0.0452489 2236.8; 0.0449438 2073.6; 0.030303 1571.9; LOAD COMB 12 LC1(OBE) 1 1.0 2 1.0 6 1.0 LOAD COMB 13 LC2(OBE) 1 1.0 2 1.0 7 1.0 LOAD COMB 14 LC3(OBE) 1 1.0 2 1.0 8 1.0 LOAD COMB SRSS 15 LC4(OBE) -1 1.0 -2 1.0 6 1.0 7 1.0 8 1.0 1 LOAD COMB 16 LC1(OBE WITH -VE SL) 1 1.0 4 1.0 6 1.0 LOAD COMB 17 LC2(OBE WITH -VE SL) 1 1.0 4 1.0 7 1.0 LOAD COMB 18 LC3(OBE WITH -VE SL) 1 1.0 4 1.0 8 1.0 LOAD COMB SRSS 19 LC4(OBE WITH -VE SL) -1 1.0 6 1.0 7 1.0 8 1.0 -4 1.0 1 PERFORM ANALYSIS PRINT STATICS CHECK FINISH FINISH
Are you trying to check for resonance? It is not required for this case.
No, only seismic qualification of structure is needed.
Doubt is whether any check on frequency of structure to be done.. i. e whether we need do have the structure above any frequency based Response spectrum used
As you are performing RSA, the program will go for modal extraction. You need to keep an eye if the frequency of modes are very high or low.