大跨宽幅双提篮系杆拱桥动力特性和抗震性能

为研究大跨度宽幅双提篮系杆拱桥结构的动力特性,采用了三维数值模拟方法进行分析,并运用共同节点而选用不同截面和材料的方法分别建立钢管混凝土拱桥中钢管和混凝土单元来模拟两者力学性能上的差异。以石家庄市拟建的友谊大街钢管混凝土拱桥为例,研究了其动力特性和抗震性能。计算结果表明:该拱桥结构整体刚度较大,桥梁竖向刚度和纵向刚度大于其横向刚度;横撑增强了拱肋的扭转约束,提高了拱肋面外稳定性;立柱增强了桥面的竖向刚度。在地震荷载作用下,桥梁不同部分对地震的响应不同;在激励强度相同的条件下,横桥向激励对该桥的影响大于顺桥向激励;从整体上看,当最大地震动加速度峰值不大于0.10g时,桥梁结构是安全的。

Dynamic Characteristics and Aseismatic Performance of Long-Span and Broad-Width Double-Basket-Type Tied-Arch Bridge

Abstract ??The three-dimensional numerical method was used to study the dynamic characteristic of the double basket type concrete-filled steel tube tied-arch bridge with long-span and broad width. To simulate the different mechanical properties between steel tubes with concrete, concrete and steel tube elements were established with the same nodes but different sections and materials. The Friendship Avenue Bridge in Shijiazhuang was taken as an example to analyze its dynamic characteristic and seismic response which was a double basket type concrete-filled steel tube tied-arch bridge. The simulation results showed that the whole rigidity of the bridge was large enough, while the vertical and the longitudinal rigidity were bigger than the lateral one. The rotational restraints and the lateral stability of the bridge were enhanced by the lateral braces; the vertical stiffness of the deck was strengthened by the columns. Under the earthquake excitation, different parts of the bridge had different response. With the same strength of excitation, the lateral earthquake excitation had larger effects on dynamic response of the bridge than the longitudinal excitation. Generally, the bridge is safe when the maxim earthquake acceleration was less than 0.10g.