Seismic Design Example Static Procedure IBC 2003 ASCE 702 NFPA 5000

Given. A 12-story building located in downtown, Los Angeles, California. The building properties summarized in Fig. 2.46 are the same as those used in the 1997 UBC example, Section 2.13.19.1.

Occupancy group = II (Table 2.13 ASCE Table 1.1)

SDC = D (Tables 2.17 and 2.18; ASCE Tables 9.4.2.1a and b)

Site class as determined by project geotechnical engineer = D

Static Seismic Force
Figure 2.46. Design example; ASCE 7-02 (IBC-03), static force procedure.

Building's lateral load system = SMRF with EBF

(Table 2.21 ASCE Table 9.5.2.2) Elastic fundamental period, TB from computer analysis = 2 secs Total seismic weight, W = 22,680 kips Building height hn, above shear base = 160 ft Mapped MCE, 5% damped, Spectral acceleration at short periods, SS = 1.5 Mapped MCE, 5% damped,

Spectral response acceleration at a period of 1 second, S1 = 0.6.

Required. Using the equivalent lateral force procedure of ASCE 7-02 determines the following:

Seismic base shear, V Vertical distribution of base shear V Seismic story shear Overturning moment Diaphragm design forces Allowable story drifts

Solution. Seismic design coefficients

Acceleration-based site coefficient (at 0.2 sec period), Fa = 1

Velocity-based site coefficient (at 1.0 sec period), Fv = 1.5

MCE spectral response acceleration at short periods for site class effects, SMS = Fa Ss = 1 x 1.5 = 1.5 ASCE Eq. (9.4.1.2.4.1)

MCE spectral response acceleration at a 1-sec period adjusted for site class effects, SM1 = Fv x S1 = 1.5 x 0.6 = 0.9 ASCE Eq. (9.4.1.2.4)

Design, 5% damped, spectral response acceleration at short periods, SDS = 2/3Sms = 2/3 x 1.5 = 1.0 ASCE Eq. (9.4.1.2.5.2)

Design, 5% damped, spectral response acceleration at a 1-sec period, SD1 = 2/3Sms = 2/3 x 0.9 = 0.6 ASCE Eq. (9.4.1.2.5.2)

Occupancy importance factor, I = 1 (Table 2.13; ASCE Table 9.1.4)

Response modification coefficient, R = 8.0 (Table 2.21; ASCE Table 9.5.2.2)

System overstrength factor, Qo = 2.5 (Table 2.21; ASCE Table 9.5.2.2)

Coefficient for upper limit on calculated period, Cu = 1.4

TABLE 2.23 Coefficient for Upper Limit on Calculated Period

Design spectral response acceleration at 1 Second, SD1 Coefficient Cu

TABLE 2.23 Coefficient for Upper Limit on Calculated Period

> 0.4

Was this article helpful?

0 0
Renewable Energy 101

Renewable Energy 101

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.

Get My Free Ebook


Post a comment