Seismic Performance Analysis Of Half-through Suspension Deck Tied Arch Bridge

The half-through suspension deck tied arch bridge has been built and developed in China,and has greatly improved in span.However,in recent years,the phenomenon of collapse and destruction of such bridge type in actual operation has been continuously appeared.At present,the half－through suspension deck tied arch bridge is also constructed in the seismic zone,but its seismic performance has not been studied in depth.Therefore,this paper mainly studies the seismic problem of the half-through suspension deck tied arch bridge.The main work is as follows:(1)The structural characteristics of the half-through suspension deck tied arch bridge and the recent collapse and damage of the operation are introduced.The status quo of seismic research and seismic test research related to it is expounded.(2)Based on the Jiangnan railway overpass in the 8 degree seismic intensity,the finite element model of the half-through suspension deck tied arch bridge was established by using Midas Civil software.The model calculation results were verified by the bridge static load test data.Then the results of the self-vibration characteristics of the bridge are analyzed and compared,and compared with the calculation results of the self-vibration characteristics of the relevant literature,it is judged that the model built in this paper has practical engineering usability.(3)Using three near-fault and three far-seismic seismic waves as input,the seismic response of the half-through suspension deck tied arch br:idge(mainly arch rib)under-various seismic waves is analyzed.The results show that it is reasonable to use three-way seismie wave input in seismic load time history analysis.(4)The influence of adding lateral support on the seismic performance of the bridge is studied.The increase of the lateral support reduces the first-order mode period by 15%,which has a certain influence on the lateral vibration mode of the bridge.The results of time-history analysis show that the addition of diagonal braces to the arched roof makes the half-through suspension deck tied arch bridge have better seismic effect.Under the action of transverse seismic waves,the internal force of the dome can be significantly reduced,(5)Using the seismic demand capacity ratio method to evaluate the seismic performance of the half-through suspension deck tied arch bridge,the results show that the boom and beam have the strongest seismic capacity,and the arch ribs and cross braces are the weak links of the tied arch bridge,and the seismic capacity.It is weak,and it is prone to plastic deformation under the action of strong earthquakes and gradually breaks down.The addition of the vault bracing can improve the seismic Performance of the arch ribs and cross braces atthe vault,but does not have nuch influence on the boom and the beam.