基于多因素分析的桥梁结构地震滞回耗能比值谱研究

Research on Seismic Hysteretic Energy Dissipation Ratio Spectra for Bridge Structure Based on Multi-factor Analysis

以3种场地下的214条近断层地震记录为输入,以分别简化为理想弹塑性、双线性和刚度退化滞回模型的单自由度体系的桥梁结构在大量近场地震作用下的滞回耗能分析为基础,从地震动特征和结构特性2个角度分别定量讨论了多种因素对结构滞回耗能比值谱的影响规律;用数值计算结果对比验证了各学者所建议模型存在的不足,并用统计回归方法建议了适用于0~15 km近断层范围内的滞回耗能比值谱。结果表明：决定滞回耗能分配比例的主要因素是结构阻尼、延性系数和结构自振周期;所建议的比值谱能更全面地反映影响能量分配的主要因素,且取值更符合实际地震动的能量分配特征,可用于基于能量原理的桥梁结构抗震设计。

Regarded 214 near-fault earthquake records with 3 kinds of soil sites as excitation,based on hysteretic energy dissipation analysis of bridge structures simplified respectively as SDOF system with elastic-perfectly plastic（EPP）,bilinear（BL） and stiffness degradation（SD） hysteretic models under lots of near-field seisms,the influences of multiple factors on hysteretic energy dissipation ratio spectra for seismic structure from aspects of seismic ground motion and structural characteristic parameters were investigated quantitatively.The defect of the proposed energy ratio models by other scholars was discussed with numerical results,and an improved model was developed by statistical regression method,which was applicable for hysteretic energy dissipation ratio spectra within the region of 0 to 15 km near-fault distance.Results show that the major factors for hysteretic energy distribution ratio are structural damping,ductility coefficient and self-vibration period of the structure.The advised energy dissipation ratio spectra can more effectively reflect the main factors which influence energy distribution,and the spectra value is more consistent with the energy distribution characteristics of actual seismic ground motion which can be used for energy-based seismic design of structures.