【摘要】 以武广客运专线上一座钢桁拱桥为例,运用结构最优化理论建立了考虑地震时车辆运行安全性的铁路钢桁拱桥模型,采用ANSYS中的零阶优化方法对其减隔震支座进行优化设计,在优化过程中考虑Rayleigh阻尼系数的变化对减隔震体系的影响,实现了对铅芯橡胶支座动力设计参数的优化。通过计算分析,得出了铅芯橡胶支座动力参数对桥梁地震响应的影响规律:在应用LRB对不同场地条件下的铁路钢桁拱桥进行减隔震设计时,屈服后刚度与屈服前刚度比α对结构地震响应有重要影响。因此,可以采用改变屈服后刚度与屈服前刚度比α的简化设计方法,满足桥梁地震响应的要求。为了提高系统的优化效率,在进行减隔震支座优化时,行车安全性的约束可以在优化过程外考虑,即在支座参数优化解确定后,再进行车辆地震输入谱密度强度SI值的验算。更多还原

【Abstract】 Taking the safety of vehicles during the earthquake into account,the present paper established a steel truss arch bridge model under structural optimization theory and optimized bearing through zero-order method in ANSYS.Considering the effect of Rayleigh damping coefficient changes in seismic isolation system,the paper also optimized dynamic design parameters of the lead-rubber bearing(LRB) at the same time.When it comes to the effect regulation of LRB dynamic parameters on earthquake response,it led to a conclusion that the ratio α of post-yield and pre-yield stiffness had a significant impact on the earthquake response of the structure when applied LRB in seismic-isolated design of steel truss arch bridge in various construction sites.Hence,it can meet the earthquake response requirement through a simplified method of changing the ratio α.During the bearings optimization,it should consider the traffic safety beyond the optimization process in order to improve the optimized efficiency.That means it should checks the the value of spectral-density intensity(SI) after getting the optimized solutions of bearings.更多还原