汶川百花大桥震害分析与抗震性能研究

摘要

以遭到严重震害的汶川百花大桥为研究对象,从抗震设计的角度出发,用反应谱法和时程法进行了第一级设防水准(E1)地震作用下的弹性分析,用非线性时程法进行了第二级设防水准(E2)地震作用下的弹塑性分析,并综合分析了该桥的震害原因和抗震性能,为同类桥梁的设计提供参考和借鉴.分析结果表明:双柱式柔性墩的采用导致该桥整体刚度较小；桥墩纵筋和箍筋的配置不足导致了E1地震下的承载力不足,而E2地震下的塑性变形是满足要求的；固定墩处支座设置和系梁布置的不合理导致了固定墩左墩柱受到严重破坏；第五和第六联之间刚度差别较大而牛腿(悬臂支托)的支承长度过小,导致该牛腿处发生了落梁破坏.%Wenchuan Baihua Bridge, which was seriously damaged in the earthquake, was chosen as the object of study. Elastic analysis under earthquake action El was performed with both response spectrum method and time-history method,and elastoplastic analysis under earthquake action E2 was performed with nonlinear time-history method. In the end, causes of the damage and aseismic behavior of the bridge were summarized in order to provide design references for similar bridges. The studies show that: l)the use of double-columns flexible piers decreased the integral stiffness; 2)the deficiency of longitudinal bar and stirrup in the piers leads to the low bearing capacity under E1, while the plastic deformation under E2 can meet the standard; 3) the unreasonable layout of bearings and tie beams causes the severe damage of the left column of the fixed piers; 4)the small bearing length of the bracket, together with the big stiffness gap between the fifth and sixth continuous beam, lead to the falling down of the superstructure.