Research on Seismic Mitigation and Isolation Design for High-speed Railway Multi-span and Long-unit Extradosed Bridge
The multi span long continuous beam structure has problems such as high seismic force on fixed piers and difficulty in restoring ductile parts after earthquakes,making it difficult to design earthquake resistant structures in high-intensity seismic areas.In order to solve the seismic design problem of multi span long connected low tower cable-stayed bridges on high-speed railways,a span of(65.65+8×110+65.65)m single cable plane prestressed concrete low tower cable-stayed bridge was studied,and three different seismic system schemes,namely single fixed pier,rigid continuous beam,and friction pendulum bearing isolation,were analyzed and compared using nonlinear time history integration method.The research results indicate that the use of friction pendulum bearing isolation system has obvious advantages.Under design earthquake action,compared with a single fixed pier system,the transverse bending moment of the bridge pier is generally reduced by more than 70%,and the longitudinal bending moment of the fixed pier is reduced by about 80%.Further analysis of the parameters of the friction pendulum isolation support was conducted to determine appropriate support parameters,resulting in better support deformation and pier top shear force,with significant seismic reduction and isolation effects.The research conclusion is that in the case of small shear span ratio of bridge piers and high stiffness of the lower structure,the installation of friction pendulum isolation bearings can significantly reduce the seismic response of the lower structure during earthquakes,making each bridge pier uniformly stressed.At the same time,reasonable bearing design can meet the needs of large earthquake displacement and have sufficient self resetting ability.
high-speed railwaymulti-span and long-unit continuous beam structureextradosed bridgeseismic mitigation and isolation designfriction pendulum bearinghigh-intensity seismic zone
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维普
