工程结构等强度位移比谱影响因素分析

应用等强度位移比谱估计现有结构在不同地震动强度下的最大弹塑性位移是一种十分简单有效的方法．利用大量单自由度体系在不同强震记录作用下的弹塑性动力时程分析结果，分析讨论了场地条件、结构的屈服强度、周期及恢复力模型等因素对等强度位移比谱的影响规律，其中重点从定性到定量详尽研究了阻尼和恢复力模型的影响．结果表明：阻尼和恢复力模型对等强度位移比谱的影响，不但随场地的不同而不同，而且受屈服强度系数及单质点体系周期的影响较大；要精确考虑阻尼和恢复力模型对等强度位移比谱的影响，必须根据结构的场地条件、屈服强度系数及周期确定．最后，给出了阻尼和恢复力模型影响等强度位移比谱的修正公式．

Influence analysis on displacement ratio spectra of constant yielding strength for evaluation of existing structures

In the evaluation of existing structures with known lateral strength, the displacement ratio spectra of constant yielding strength that provide inelastic displacement ratios to estimate maximum lateral inelastic displacement demands on existing structures from maximum elastic displacement demands are particularly useful. The influence of site conditions, period of vibration, level of lateral yielding strength, damping and hysteretic model et. al on displacement ratio spectra of constant yielding strength are investigated in this paper. And the special emphasis is given to influence analysis of structure damping and hysteretic model on the inelastic spectra. A statistical study are performed of inelastic displacement ratios computed for SDOF systems with different levels of lateral yielding strength normalized to strength required to retain elastic when subjected to a large number earthquake accelerations recorded in four groups of soil conditions. Different damping ratio and hysteretic model of systems are considered. It is concluded that the damping and hysteretic model effects on displacement ratio spectra of constant yielding strength are rather complex. It depends on not only site conditions but also the level of yielding strength and the natural period of structures as well. Finally, results from non-linear regression analysis are presented that provide a simplified expression to be used to approximated quantify the mentioned effects influence.