The Design Parameters Of Long-span Continuous Prestressed Concrete Beam Bridge Seismic Response Analysis

The research in this paper is an important part of the 3D analysis of dynamic and seismic response of curved long span bridges with high piers, which is the sub project of the research of the design and construction technology of curved long span bridges with high piers, one of the national transportation development scientific project in the western regions. It is necessary to study the seismic response of bridge for designing reasonable earthquake resisting structures and developing effective earthquake resisting methods. On the basis of the basic theory of the seismic response analysis, the paper draws lessons from the built bridge and the newest research achievement, studies and analyzes dynamic parameter design of long span prestressed concrete continuous beam bridge, obtains some valuable conclusions which will give some reference for practical earthquake resisting designing of continuous beam bridges.Calculation models of the large-span continuous girder bridge are proposed with finite methods respectively .Time history analysis is applied to study the effect of sensitive parameters of the bridge type on the dynamic behavior seismic response of continuous beam.For all of calculation of straight continuous girder bridge, only longitudinal excitations is carried out. Considered the effect of different parameters include height of piers, span length, spans of bridge, ratio of side to main span, stiffness of brake piers, constrain types. The rules of different parameter effect on seismic response of straight continuous beam are drawn. As to curved continuous girder bridge, the factors considered include ratio of main span to radius of curvature, excitation orientation, spans of bridge, ratio of side to main span, stiffness of brake piers, eccentricity of central piers,. constrain types. The rules of different parameter effect on seismic response of curved continuous beam are drawn. The comparison between straight and curved continuous beam bridges is conducted at the same time.Based on a great of amount of numerical analyses, the paper obtains the following conclusions: For straight long span continuous girder bridge, the bridge seismic resisting benefits from the adding height of piers and spans of bridge; The change of span length and ratio of side to main span influencing seismic resisting is advantage and drawback running concurrently; Reducing stiffness of brake piers is favorable for seismic resisting; The change of constrain types have little effect on seismic resisting. For curved long span continuous girder bridge, increasing ratio ofmain span to radius of curvature is good for girder seismic resisting; Excitation orientation has a great influence on seismic resisting; Increasing spans of bridge, ratio of side to main span, stiffness of brake piers is unfavorable for seismic resisting of structure; Pay more attention to choose eccentricity of central piers and constrain types.