Three Seismic Design Methods Comparison Study Of Continuous Beam Bridge

With the rapid development of transportation,especially high-grade highways, cantilever bridge with mult-expansion joints and T-shaped rigid frame bridge will not be able to meet the requirement of driving smoothly and comfortable,which makes the statically indeterminate continuous girder bridge with its outstanding merits of structural stiffhesslarge,small deformation,expansion joints and driving smoothly and comfortable to get a rapid development. Concrete continuous box girder is mature and general in the form of bridges,has been widely used in many cross-sea projects which have been built or under construction.Currentlly,China is facing a severe earthquake situation and the continuous beam bridge is more and more widely used in engineering practice, to correct the seismic design of bridge engineering for the infrastructure construction in China has been leading an increasingly important role.This article make the16th Road cross-sea bridge engineering which located in Dalian puwan new area as the background, using the Midas/Civil finite element software to calculate a span of an associated continuous beam bridge (3x50m) dynamic response under the two seismic fortification criterions with response spectrum analysis and time history analysis approach.The structure will enter the plastic state under the earthquake action E2,the paper will use the following programs for seismic design:(1) The formation mechanism of the plastic hinge in the length of plastic hinge at the base of the fixed pier is used for the ductility analysis of the structure;(2) Lead rubber bearing is used for the seismic isolation design of the structure;(3) The Lock-up instantly locking device is used to make the piers to shared seismic forces excited by earthquake action E2.The results of three programs of seismic design in continuous girder bridge show that:any of the program can be effective enough to reduce the structural seismic forces excited by earthquake. Ductility analysis use the formation mechanism of the plastic hinge at the base sections of the fixed pier to get into the plastic states, to avoid the collapse of the structure. Lead rubber bearings for seismic isolation design of the structure can change the seismic energy to seismic isolation devices, greatly reduce the seismic forces to the important components on the structure, and the maximum shear displacement of the lead rubber bearing is less than the shear displacement allowed, to avoid damage of structural components. Lock-up devices can effectively reduce the seismic force exerted on fixed pier,but the seismic effect is less obvious than the other two programs.