Effect of Ballastless Track on Seismic Response of Simply-supported Girder Bridges under Different Terrain
Research purposes:In order to study the influence of CRTS Ⅱ slab ballastless track system on the seismic response for the multi-span simply supported girder bridge,integrated track and bridge model and single pier model were established respectively for the 32 m simply supported girder bridge.The influence of track longitudinal constraint effect on seismic response of piers under three typical terrain conditions is studied by response spectrum method.Research conclusions:(1)When crossing flat terrain,under the influence of track system and end spikes,internal forces at the bottom of pier in the integrated track model show a parabolic distribution with small magnitude at boundary span and large magnitude at middle span.Compared with the single pier model,the piers in the middle span region are located in the seismic response amplification zone.(2)When crossing the V-shaped terrain,internal forces at the bottom of each pier in this area present the U-shaped distribution characteristics of significantly increasing internal forces at the bottom of critical pier and significantly decreasing internal forces at the bottom of middle-span tall pier.(3)When crossing the ∧-shaped terrain,internal forces at the bottom of piers in the region show the ∧-shaped distribution characteristic,with the middle span low pier as the center,and internal forces at the bottom of its piers increase significantly while those at the bottom of adjacent piers decrease significantly.Therefore,the middle span low pier should be paid more attention in the seismic design.(4)The research conclusions could be applied to the seismic design of high-speed railway simply supported girder bridge with similar to typical terrain conditions.
high-speed railwaysimply supported girderintegrated track and bridge modelpierseismic response
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