【摘要】 曲线梁桥因线形、刚度及质量的不规则分布,需研究其地震动最不利输入方向。Bresler屈服面给出钢筋混凝土构件在轴压力与双向弯矩组合作用下的截面屈服条件,据此将地震中桥墩截面最易发生屈服的方向定义为最不利地震动输入方向。在应用反应谱法得到两个正交方向地震反应的基础上,提出基于Bresler屈服面的地震动最不利输入方向的新算法,该法考虑水平面内双向地震动共同作用及曲线梁桥振型间的相关性。给出基于时程分析法的地震动最不利输入方向确定算法。并以某闭合圆环匝道桥为对象,分析其各墩的地震动最不利输入方向,验证方法的准确性。更多还原

【Abstract】 Considering the irregular geometry,stiffness and mass distribution,the critical angle of seismic incidence for curved bridges was investigated.The yield condition for concrete structure under axial compression and biaxial flexural moments were well depicted with Bresler Yield Surface,the most vulnerable direction for piers was therefore defined as the critical angle of seismic incidence.Based on obtaining the seismic responses in two orthotropic directions with the response spectrum analysis,a new algorithm was proposed considering multicomponent ground motion and the correlation of natural vibration modes.Furthermore,procedures for time history analysis were developed.Finally,an example of a closed circular ramp was given to illustrate the validity of the method.更多还原