Analysis On Earthquake Response Of Curved Viaduct With Pile-soil-structure Coaction

Nowadays, urbanization in our country is very rapid, for the settlement of the urban traffic jam,viaducts are quickly being built. The difference between urban viaduct and other kinds is that they are located in urban areas, is confined by architectures and have to meet the request of the road lines, so relatively more of them are of slope and curved line. Moreover, viaducts are important for economy in city development and component of life blood in urban disaster relief. They are destroyed heavily in earthquake, and the effect of pile-soil-structure is significant.Referring to some viaduct in third ring in Xi'an city ,four models in this paper have been set up such as simple bridge model considering pile-soil coaction, simple bridge model considering consolidation of cushion cap, rigid bridge model considering pile-soil coaction, rigid bridge model considering consolidation of cushion cap. The frequency and modes are calculated, the mode shapes and characters are discussed ,and the pile-soil-structure coaction impact on the dynamic characteristics of curved viaducts are analyzed.Dynamic response spectrum method and dynamic history analysis method are utilized; the stress and deformation of curved viaducts are obtained; the results are compared to analyze the influence level and rules on curved viaducts considering pile-soil-structure ; some earthquake response traits and some rules about curved viaducts are obtained.The model with the pile-soil-structure coaction considered has higher flexibility, more displacement on pier top, less stress response on pier bottom and more lateral moment on main girder. The model with cushion cap fixed, has bigger rigidity, less displacement on pier top for more confinement. It has nothing to do with the lengthwise girder displacement whether the pile- soil-structure coaction is considered or not. Under effect of the three earthquake waves, the curve of stress envelope diagram has coarse symmetry no matter whether the pile-soil-structure coaction is considered. The study results provide some conclusions for the research on the stress traits of curved viaduct under earthquake action, and it gives a real case for the study on pile-soil-structure coaction , which will prompt the curved viaduct design to go forward and boost its own development.