适用于高层RC结构的谱加速度指标分析

ANALYSIS OF SPECTRA ACCELERATION AS AN INTENSITY MEASURE ADAPTED TO RC HIGH-RISE BUILDINGS

地震动强度指标是影响结构地震风险评估准确性的重要参数。为此,基于12榀高层RC结构的增量动力分析结果,首先计算了谱加速度指标在不同周期下的有效性和充分性,考察二者与高阶振型和非线性软化效应的相关性,进而分析反应谱的控制周期值,并据此提出适用于该类结构的多周期平均谱加速度指标。研究表明:谱加速度指标的有效性和充分性随反应谱周期取值的不同波动性较大,受高阶振型和非线性软化效应的影响;与既有地震动强度指标相比,该文提出的多周期平均谱加速度指标的有效性显著提高,对于该类结构具有较好的适用性。

Intensity measure is a key parameter affecting the accuracy of seismic risk assessment. Thus based on the incremental dynamic analysis results of 12 RC high-rise structures, both efficiency and sufficiency of spectral acceleration at different periods are calculated. Then the effects of higher modes and periods softening on them are investigated. Moreover, controlling periods across the spectrum are also studied to put forward a new intensity measure which is the geometric mean of spectra accelerations values at certain periods. The results suggest that the efficiency and sufficiency are obviously fluctuated with increasing spectrum periods, and influenced by the effects of higher modes and periods softening. The proposed intensity measure is more efficient than some existing ones, showing its fitness to RC high-rise structures.