The maximum considered earthquake spectral response acceleration for short periods,
SMS, and at 1-second period,
SM1, adjusted for
site class effects shall be determined by Equations 16-37 and 16-38, respectively:
where:
| Fa | = | Site coefficient defined in Table 1613.3.3(1). |
| Fv | = | Site coefficient defined in Table 1613.3.3(2). |
| SS | = | The mapped spectral accelerations for short periods as determined in Section 1613.3.1. |
| S1 | = | The mapped spectral accelerations for a 1-second period as determined in Section 1613.3.1. |
TABLE 1613.3.3(1) VALUES OF SITE COEFFICIENT Fa a | SITE CLASS | MAPPED SPECTRAL RESPONSE ACCELERATION AT SHORT PERIOD |
| Ss ≤ 0.25 | Ss = 0.50 | Ss = 0.75 | Ss = 1.00 | Ss ≥ 1.25 |
| A | 0.8 | 0.8 | 0.8 | 0.8 | 0.8 |
| B | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 |
| C | 1.2 | 1.2 | 1.1 | 1.0 | 1.0 |
| D | 1.6 | 1.4 | 1.2 | 1.1 | 1.0 |
| E | 2.5 | 1.7 | 1.2 | 0.9 | 0.9 |
| F | Note b | Note b | Note b | Note b | Note b |
| a. Use straight-line interpolation for intermediate values of mapped spectral response acceleration at short period, Ss. |
| b. Values shall be determined in accordance with Section 11.4.7 of ASCE 7. |
TABLE 1613.3.3(2) VALUES OF SITE COEFFICIENT FV a | SITE CLASS | MAPPED SPECTRAL RESPONSE ACCELERATION AT 1-SECOND PERIOD |
| S1 ≤ 0.1 | S1 = 0.2 | S1 = 0.3 | S1 = 0.4 | S1 ≥ 0.5 |
| A | 0.8 | 0.8 | 0.8 | 0.8 | 0.8 |
| B | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 |
| C | 1.7 | 1.6 | 1.5 | 1.4 | 1.3 |
| D | 2.4 | 2.0 | 1.8 | 1.6 | 1.5 |
| E | 3.5 | 3.2 | 2.8 | 2.4 | 2.4 |
| F | Note b | Note b | Note b | Note b | Note b |
| a. Use straight-line interpolation for intermediate values of mapped spectral response acceleration at 1-second period, S1. |
| b. Values shall be determined in accordance with Section 11.4.7 of ASCE 7. |
