EVALUATION OF ASCE/SEI 7 EQUATIONS FOR SEISMIC DESIGN OF NONSTRUCTURAL COMPONENTS USING CSMIP RECORDS
by Saeed Fathali and Bret Lizundia
Saeed Fathali and Bret Lizundia (2012). EVALUATION OF ASCE/SEI 7 EQUATIONS FOR SEISMIC DESIGN OF NONSTRUCTURAL COMPONENTS USING CSMIP RECORDS SMIP12 Seminar on Utilization of Strong-Motion Data, p. 1 - 18.
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A recently completed California Strong Motion Instrumentation Program (CSMIP) data interpretation project used recorded ground and floor motion data to evaluate a key ASCE/SEI 7-05 (and 7-10) equation for seismic design of acceleration-sensitive building nonstructural components. CSMIP motions from 73 earthquakes recorded in 151 fixed-base buildings were used in the evaluation. An improved equation was developed with two categories of revisions. First, the current code formula considers a linear relationship between the peak floor acceleration (PFA) and relative height of the component in the building with a roof PFA that is three times that of the peak ground acceleration. The analyses of the recorded motions showed that improved results could be obtained by using a nonlinear relationship and by considering both the building approximate period, Ta, and the level of ground motion. Second, the code formula considers a component amplification factor, ap, that takes values between 1.0 and 2.5 depending on the flexibility of the nonstructural component. Analyses showed that component amplification factor can be better represented using a three-segment spectrum composed of a linear rise from 1.0 to maximum value of ap at short periods, a flat segment with the maximum value of ap at medium range periods, and a nonlinear decaying segment at longer periods. The shape and amplitude of the spectrum was found to vary depending on Ta.