A Primary Study Of The Design Method Of The Tie Beam Of Double-column Pier In The Seismic Design Of Bridges

With the rapid development of China’s economy,China’s highway and bridge construction has also developed very rapidly.At present,the total number of highway bridges in China is close to 800,000,among which the number and proportion of small and medium span bridges are the largest.This type of bridge is usually a simplely supported girder bridge or continuous girder bridge,the substructure of this kind of bridge is generally designed as double column or multi-column pier.For the double column pier structure,when the pier height is relatively high,the horizontal tie beams are often needed to set in order to improve the stability and the seismic performance of the bridge structure.For a bridge designer,it is necessary to choose a reasonable horizontal tie beam arrangement according to the actual situation of the project.The setting of the tie beam is often closely related to the seismic performance of the bridge structure.In the seismic design of the bridge,the transverse tie beam generally acts as a ductile member,which consumes the ground motion energy and reduces the seismic response of the structure through its own plastic deformation.Under normal and rare earthquakes,transverse tie beams are often used as a tool to improve the seismic performance of bridge structures,and often should be designed to achieve some kind of expected seismic damage.At present,design specifications have not given clear rules of how to set the tie beams,and the design method and the set principle of the tie beams are still relatively lacking.In this paper,a primary study of the design principle and design method is done,and the following questions are discussed:1、Why should the bridge set the tie beam。2、Under what circumstances the tie beams are needed to set。3、How to design the tie beams。In view of the above problems,the following work has been done in this paper :1、Based on a series of compulation of different bridge models with different height of double column pier without the tie beams,a comparative analysis of the internal force distribution characteristics of the double column pier is studyed,and the purpose and significance of setting tie beams are discussed.2、The relationship of the height of the pier and the reasonable number of the transverse tie beams has been studyed.3、Based on a series of seismic analysis of different bridge models with different height of double column pier and different layout and different cross section design of the tie beams,the reasonable layout of the tie beams and the reasonable cross section design of the tie beams have been studyed.4、The setting principle and the design method of the transverse tie beam during the seismic design of the bridge are summarized.