Study On Seismic Performance Of Beam-Arch-Hybrid Bridge And Engineering Practice

Beam-arch-hybrid bridge is an innovation of beam-bridge and arch-bridge,which has the merits of both of the two traditional types of bridge.Because of external thrust is non-essential,beam-arch-hybrid bridge can accommodate soft soil conditions.Three span continuous beam-arch-hybrid bridges are competitive among the span range of 60 m to 200 m in urban areas.Specifications available still cannot be used to design long-span continuous beam-arch-hybrid bridges directly,and the study on seismic response of long-span continuous beam-arch-hybrid bridges is inadequate up to now.Because of this background,based on ample literature researches,a finite element model of three-span deck type bridge is constructed,and then vulnerability of bridge components has been identified.On this basis,seismic isolation measures have been studied and a method which can improve bridge seismic response significantly been advised.The main points of this paper are listed below.(1)Bridge seismic fortification criterion and performance objectives are settled based on actual engineering situation.Then the bridge components which are susceptible to earthquake are recognized.(2)Several seismic isolation measures have been designed according to bridge failure mechanism,and the most effective one been ascertained by nonlinear time history analysis.(3)After the efficient seismic isolation method has been selected,several parameters associated with it still need to be optimized according to which can reduce the moment and shear forces of the pile caps mostly.What is crucial for bridges with seismic isolation design is to make sure the seismic isolation devise perform normally.Moreover,beam falling-off prevention measures are necessary to accommodate with the large displacements under earthquake.For piles and transition piers,construction measures should be adopted to provide sufficient ductility ability and shear strength.