组合设计谱确定新方法研究

AN IMPROVED METHOD ON THE DETERMINATION OF COMBINED DESIGN SPECTRUM

设计谱是各类工程结构抗震设计的基本依据,合理的设计谱取值事关抗震结构的安全性和经济性。针对组合三联设计谱传统标定方法中存在的问题,基于世界范围内最新的强震记录,对相关的地震动参数和反应谱进行了分析研究。统计中采用加权平均代替算术平均计算地震动幅值间的关系,使设计地震动幅值的确定更具合理性;提出了一种随周期(T)连续变化的规准化参数分别用于设计谱加速度、速度和位移控制段的标定,解决了组合设计谱各区段分别采用三个固定参数(PGA、PGV、PGD)标定时带来的不连续问题;将改进的设计谱与其他方法设计谱进行了比较。最后通过离散性分析和有效性检验验证了新标定方法的可靠性。

Design spectra are basic criteria for seismic design of engineering structures. Appropriately chosen spectra are essential for safety and economic efficiency of structures. To overcome the inherent problems in conventional approaches, relevant ground motion parameters and response spectra are studied by using the ground motion data recorded from the recent worldwide strong earthquakes. The relationships between ground motion amplitudes are evaluated by the weighted average method instead of the arithmetic average method, which introduces a more reasonable calculation of the design ground motion amplitudes. A normalized parameter varying with period(T) is applied when calibrating combined design spectra, and thus the asymptotically incorrect behavior caused by the three individually fixed parameters(PGA, PGV, PGD) in the calibration process of the response spectrum is rectified. Subsequently, the improved design spectrum is compared with those derived from other conventional approaches. The accuracy and reliability of the proposed procedure are examined by the discreteness analysis and validity assessment of ground motion response spectra.