地震作用下中小跨度梁桥横向碰撞参数影响分析

地震作用下挡块与主梁的横向碰撞是影响桥梁结构地震响应的重要因素,目前缺乏针对城市高架桥中广泛使用的双柱式小箱梁结构横向碰撞问题的研究。以此类桥梁的典型工程为代表,建立了空间有限元模型,利用Kelvin模型对横向碰撞进行了准确模拟,重点探讨了接触单元刚度、挡块-主梁间隙、桥墩墩高、场地类别、上部结构与盖梁质量比等关键因素对双柱式小箱梁结构桥梁地震响应的影响。研究结果表明:碰撞刚度、碰撞间隙对双柱墩墩底内力有较大影响,应尽可能通过试验予以确定;场地特性、上部结构和盖梁质量比、桥墩高度等设计参数,均会对桥梁的地震受力产生较大影响,因而应在设计选型时进行适当的调整,并尽可能选择坚硬场地下高墩轻质主梁结构体系,研究成果可为同类高架桥的设计提供技术支持。

Parametric analysis of transverse collison in middle and small span bridges under earthquake excitaiton

Transves collisions between restrain block and main girder under earthquake excition are the important factors that affect the seismic response of the bridge. Recent researches lack of dicussion on the lateral collision problems related to the Double-Column and Box-Girder Bridge(DCBGB) which is widely used in urban viaduct. Taking a bridge as an example, this paper established the spatial finite element model, the lateral collision is accurately simulated through the Kelvin-model. Then the key factors that affect the seismic responses of the DCBGB, such as the impact stiffness, the restrain block - main girder gap, height of bridge pier, site category, quality ratio of the upper structure to cap beam.The research shows that: the impact stiffness and impact clearance have greater influence on the internal forces of the double column pier bottom. The factor should be confirmed by testes as far as possible. The design parameters such as site features, quality ratio of the super structure to cap beam and pier height also have great influence on the bridge seismic force, therefore design parameters should be carefully adjusted when the bridge were designed. Choosing hard site, higher piers and lightweight main girder structure system will be a good choice. In all, this research conclusion can provide technical support for the design of similar viaducts bridges.