Experimental Study And Analysis Of The Y-shape Curved Bridge Under Multi-dimensional Earthquake

Along with our country to become the world’s second-largest economy, urban traffic is growing. In order to solve or mitigate traffic congestion problems, in recent years many cities built more than a lot of bifurcation curve bridges which have graceful architectural forms, are comfort of driving and coordinate with the environment. But this kind of bridge has many connecting parts, complex structure, its stress state is far more complex than straight girder bridge, and may endure multidimensional collision damage or collapse in action of strong earthquake. The seismic response and performance of this kind of bridges is an important topic of current study, which is of great significance. A model bridge which has shape Y was made and shaking table test to simulate multidimensional earthquake imposed to the model bridge was conducted. And finite element model of the bridge was established to study seismic response and performance of the model bridge. This paper mainly did works as following:(1) Discussed damage characteristics of curved bridges and research status of domestic and abroad, studied damage phenomena of curved bridges in action of multidimensional earthquake through the shaking table test, summarized earthquake damage rule of this kind of bridges.(2) Discussed problem of the seismic theory about the action of multi-dimensional earthquake applying to design and analysis of curved bridges. Studied multi-dimensional earthquake theory and summarized relative analysis methods. Mainly methods are about: multi-dimensional spectrum method, multi-dimensional time history method(3) A Y-shape model bridge was designed and made by taking scale proportion of 1:20. Single-point, multi-dimensional excitation earthquake simulation test on shaking table was conducted to analyze: longitudinal acceleration at the top of the pier and midst span of girder, relative displacements of pier and girder, relative displacements of adjacent girders, dynamic response at the bottom of the piers; distribution law and reason of cracks at girders and piers; dynamic response difference between straight bridge and curved bridge in action of different level of earthquakes; impact of seismic response of the model bridge in action of single-dimensional, bidirectional, three-dimensional earthquake.(4) Conducted dynamic analysis of Y-shape model bridge by using large universal finite element software. E1-Centro wave at acceleration of 500 gal was input to observe dynamic response for longitudinal acceleration at the top of the pier, relative displacements of adjacent girders, axial force and shear force at the top of the pier, bending moment and torque in midst span of girders. Results showed that dynamic responses including displacement, acceleration, forces and so on, in action of multi-dimensional earthquake are larger than single-dimensional earthquake, indicating greater harm. In order to make structural dynamic calculation more coordinately to objective reality, ensure safety and reliability of structures, multi-dimensional seismic analysis are advised to put into consideration when design curved bridges.