基于复合强度指标的弹塑性输入能量谱研究

确定弹塑性SDOF体系的输入能量是基于能量的设计方法首先要解决的问题。该文从PEER强震记录数据库选取了188条地震记录并按中国规范进行了分类,采用归一化方法,根据能量谱的特征建议了一种基于复合强度指标的三段式弹性输入能量谱。在此基础上,分析了强度折减系数和阻尼比对能量谱峰值和中长周期段的影响。结果发现:强度折减系数和阻尼比对能量谱峰值的削减作用具有明显的相关性,强度折减系数较大时阻尼比对能量谱峰值的削减作用减弱。根据弹塑性能量谱影响因素的分析统计,通过二次拟合,提出了峰值和中长周期段的修正系数。最后根据研究建议了弹塑性SDOF系统能量谱的确定方法。

RESEARCH ON THE ELASTIC-PLASTIC INPUT ENERGY SPECTRA BASED ON COMPOUND INTENSITY INDICATOR

Determination of the elastic-plastic input energy for a SDOF system is a primary issue in the energy-based design approach. The paper selects 188 seismic records according to the site classification of Chinese seismic code, and then proposes three-segment elastic input energy spectra based on normalization methods. On this basis, the effect of strength reduction factor and damping ratio are analyzed on the elastic-plastic input energy spectra. The results indicate that the strength reduction factor and the damping ratio have significant impact on reducing energy spectrum peak value;the weakening action of damping ratio is impaired when strength reduction factor is bigger. According to the statistics of the influencing factors on elastic-plastic energy spectrum, the correction coefficient of the peak and long period segment is put forward through the 2-order fitting. Process to determine the elastic-plastic SDOF system energy spectra are suggested according to the study.