Seismic Response Analysis Of Large Span Bridge With Steel Pipe Piles

With the development of social economy, the number of various types of bridges in our country is increasing rapidly. However, the location of our country determines that the earthquake disaster is frequent and serious. In recent years, many destructive earthquakes have caused great casualties and economic losses, therefore, conducting the intensive studies of the seismic performance and reinforcement method of all kinds of bridges will be of great benefit to improve the safety of bridges in our country. Based on the above background, the main research work in this paper is as follows:This paper introduced the theory and analysis method of seismic response analysis of bridge structures, and the theory of the foundation’s equivalent spring rigidity, the nonlinear of the pile, the nonlinear of the pile and foundation interaction. The paper introduced the finite element model and the method of solving the relevant parameters, After loading the seismic wave, the seismic response value and distribution law of the moment and curvature of each pile are obtained. According to the bridge’s modal maps, the bending moment and curvature of the piles, the bearing type and the length of the piles, the diameter and the thickness were adjusted, and a more reasonable design scheme was obtained.Through the analysis of the research, the following conclusions can be concluded:For the piles completely buried in the foundation, the maximum bending moment under lateral seismic force appears at the top of the pile, and the reliability of the connection between the piles and the pile cap should be ensured in the design and construction. For the piles half buried in the foundation, the maximum bending moment of the pile appears in the middle of the pile, between the air and soil or water and soil, so in the design and construction, engineers should pay attention to the problem of corrosion protection, impact resistance, etc., to avoid the corrosion of the bearing capacity of this part. When adjusting the size of the pile, the seismic performance and the vertical bearing capacity should be considered comprehensively to avoid reducing the pile’s bearing capacity in the normal use state. The high strength and rigidity of piles can ensure that the piles will not be destroyed under the earthquake, but it is easy to cause the waste of materials, and can not play the steel’s characteristics of consuming energy through deformation. Therefore, if there are too many piles that can not reach the plastic state, engineers should consider to reduce the strength and stiffness of the piles appropriately. For one pile, it is feasible to use different thickness according to different depth, the measure can ensure that the bending moment and curvature of the pile under earthquake will not exceed, and will save the use of steel.The conclusion will be beneficial to improve the understanding of the seismic response characteristics of the steel pipe pile, and can also guide the seismic design and reinforcement of the bridge with steel pipe piles.