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。 Earthquake intensity index is an important parameter that affects the accuracy of structural earthquake risk assessment. Therefore, based on the results of incremental dynamic analysis of 12 榀 high-rise RC structure, the validity and adequacy of the spectrum acceleration index under different periods are calculated first, and then the correlation between them and the higher-order modes and the nonlinear softening effect are investigated. Response spectrum of the control cycle value, and accordingly proposed for the structure of the multi-period average spectral acceleration indicator. The results show that the validity and adequacy of the spectral acceleration index are different with the different volatility of the response spectrum period, which are affected by the higher-order mode and the nonlinear softening effect. Compared with the existing seismic intensity index, The validity of the multi-period average spectral acceleration indicator is significantly improved, which has good applicability to such a structure.