Question 14.3: Draw the response spectrum curves of IS:1893 code on hard so...
Draw the response spectrum curves of IS:1893 code on hard soil for 2% and 5% damping in ADRS format.
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The response spectra of IS:1893-Part 1 was presented in Chapter 8. It can be
converted in ADRS format by the procedure outlined earlier using Equation (14.26) for
a given damping.
S_{di}=\frac{T_{I}^{2}}{4\pi ^{2}} S_{ai}g (14.26)
Typical calculations are shown in Table 14.7. In the last five columns, spectral displacement has been computed for different periods (T = 0.5, 1, 1.5, 2 and 4 sec) corresponding to spectral accelerations for 2% damping. This data is used to plot constant period lines.
Table 14.7 Calculations for ADRS for IS:1893 Spectra
5% damping | 2% damping | T = 0.5 | T = 1 | T = 1.5 | T = 2 | T = 4 | |||
Period (T) | Acceleration (S_{a}/g) | Displacement (S_{d}) | Acceleration (S_{a}/g) | Displacement (S_{d}) | Displacement (S_{d}) | Displacement (S_{d}) | Displacement (S_{d}) | Displacement (S_{d}) | Displacement (S_{d}) |
0 | 0.000 | 0.000 | 0.000 | 0.000 | 0 | 0 | 0 | 0 | 0 |
0.1 | 2.500 | 0.0062 | 3.500 | 0.0087 | 0.1555 | 0.6219 | 1.3992 | 2.4874 | 9.9497 |
0.2 | 2.500 | 0.0249 | 3.500 | 0.0348 | 0.1555 | 0.6219 | 1.3992 | 2.4874 | 9.9497 |
0.3 | 2.500 | 0.056 | 3.500 | 0.078 | 0.1555 | 0.6219 | 1.3992 | 2.4874 | 9.9497 |
0.4 | 2.500 | 0.099 | 3.500 | 0.139 | 0.1555 | 0.6219 | 1.3992 | 2.4874 | 9.9497 |
0.5 | 2.000 | 0.124 | 2.800 | 0.174 | 0.1244 | 0.4975 | 1.1193 | 1.9899 | 7.9598 |
0.6 | 1.667 | 0.149 | 2.333 | 0.209 | 0.1036 | 0.4146 | 0.9328 | 1.6583 | 6.6331 |
0.7 | 1.429 | 0.174 | 2.000 | 0.244 | 0.0888 | 0.3553 | 0.7995 | 1.4214 | 5.6855 |
0.8 | 1.25 | 0.199 | 1.750 | 0.279 | 0.0777 | 0.3109 | 0.6996 | 1.2437 | 4.9748 |
0.9 | 1.111 | 0.224 | 1.556 | 0.313 | 0.0691 | 0.2764 | 0.6219 | 1.1055 | 4.4221 |
1 | 1.000 | 0.249 | 1.400 | 0.348 | 0.0622 | 0.2487 | 0.5597 | 0.995 | 3.9799 |
1.1 | 0.909 | 0.274 | 1.273 | 0.383 | 0.0565 | 0.2261 | 0.5088 | 0.9045 | 3.6181 |
1.2 | 0.833 | 0.298 | 1.167 | 0.418 | 0.0518 | 0.2073 | 0.4664 | 0.8291 | 3.3166 |
1.3 | 0.769 | 0.323 | 1.077 | 0.453 | 0.0478 | 0.1913 | 0.4305 | 0.7654 | 3.0614 |
1.4 | 0.714 | 0.348 | 1.000 | 0.488 | 0.0444 | 0.1777 | 0.3998 | 0.7107 | 2.8428 |
1.5 | 0.667 | 0.373 | 0.933 | 0.522 | 0.0415 | 0.1658 | 0.3731 | 0.6633 | 2.6533 |
1.6 | 0.625 | 0.398 | 0.875 | 0.557 | 0.0389 | 0.1555 | 0.3498 | 0.6219 | 2.4874 |
1.7 | 0.588 | 0.423 | 0.824 | 0.592 | 0.0366 | 0.1463 | 0.3292 | 0.5853 | 2.3411 |
1.8 | 0.556 | 0.448 | 0.778 | 0.627 | 0.0345 | 0.1382 | 0.3109 | 0.5528 | 2.211 |
1.9 | 0.556 | 0.473 | 0.737 | 0.662 | 0.0327 | 0.1309 | 0.2946 | 0.5237 | 2.0947 |
2 | 0.500 | 0.497 | 0.700 | 0.696 | 0.0311 | 0.1244 | 0.2798 | 0.4975 | 1.9899 |
2.1 | 0.476 | 0.522 | 0.667 | 0.731 | 0.0296 | 0.1184 | 0.2665 | 0.4738 | 1.8952 |
2.2 | 0.455 | 0.547 | 0.636 | 0.766 | 0.0283 | 0.1131 | 0.2544 | 0.4523 | 1.809 |
2.3 | 0.435 | 0.572 | 0.609 | 0.801 | 0.027 | 0.1081 | 0.2433 | 0.4326 | 1.7304 |
2.4 | 0.417 | 0.597 | 0.583 | 0.836 | 0.0259 | 0.1036 | 0.2332 | 0.4146 | 1.6583 |
2.5 | 0.400 | 0.622 | 0.560 | 0.871 | 0.0249 | 0.0995 | 0.2239 | 0.398 | 1.592 |
2.6 | 0.385 | 0.647 | 0.538 | 0.905 | 0.0239 | 0.0957 | 0.2153 | 0.3827 | 1.5307 |
2.7 | 0.370 | 0.672 | 0.519 | 0.94 | 0.023 | 0.0921 | 0.2073 | 0.3685 | 1.474 |
2.8 | 0.357 | 0.696 | 0.500 | 0.975 | 0.0222 | 0.0888 | 0.1999 | 0.3553 | 1.4214 |
2.9 | 0.345 | 0.721 | 0.483 | 1.01 | 0.0214 | 0.0858 | 0.193 | 0.3431 | 1.3724 |
3 | 0.333 | 0.746 | 0.467 | 1.045 | 0.0207 | 0.0829 | 0.1866 | 0.3317 | 1.3266 |
3.1 | 0.323 | 0.771 | 0.452 | 1.08 | 0.0201 | 0.0802 | 0.1805 | 0.321 | 1.2838 |
3.2 | 0.313 | 0.796 | 0.438 | 1.114 | 0.0194 | 0.0777 | 0.1749 | 0.3109 | 1.2437 |
3.3 | 0.303 | 0.821 | 0.424 | 1.149 | 0.0188 | 0.0754 | 0.1696 | 0.3015 | 1.206 |
3.4 | 0.294 | 0.846 | 0.412 | 1.184 | 0.0183 | 0.0732 | 0.1646 | 0.2926 | 1.1706 |
3.5 | 0.286 | 0.871 | 0.400 | 1.219 | 0.0178 | 0.0711 | 0.1599 | 0.2843 | 1.1371 |
3.6 | 0.278 | 0.895 | 0.389 | 1.254 | 0.0173 | 0.0691 | 0.1555 | 0.2764 | 1.1055 |
3.7 | 0.270 | 0.920 | 0.378 | 1.288 | 0.0168 | 0.0672 | 0.1513 | 0.2689 | 1.0756 |
3.8 | 0.263 | 0.945 | 0.368 | 1.323 | 0.0164 | 0.0655 | 0.1473 | 0.2618 | 1.0473 |
3.9 | 0.256 | 0.970 | 0.359 | 1.358 | 0.0159 | 0.0638 | 0.1435 | 0.2551 | 1.0205 |
4 | 0.250 | 0.995 | 0.350 | 1.393 | 0.0155 | 0.0622 | 0.1399 | 0.2487 | 0.995 |
The ADRS spectrum curves for 2% and 5% damping are shown in Figure 14.21.
The radial lines are constant period lines.
