Study On Mechanical Performance Of The Connection Between Pier And Cap For Accelerated Bridge Construction

Accelerated bridge construction of prefabricated and assembled bridges is one of the developing directions of bridge construction in China,which has the advantages of short construction period and low impact on surrounding environment and reducing traffic interruption time.Substructure is an important part of bridge,so the reliability and convenience of connection between precast assembled pier column and cap are particularly important.In this paper,based on an elevated main bridge project in Xuzhou,Jiangsu Province,which is implemented by accelerated bridge construction,three different connection modes of piers and caps are analyzed for mechanical properties,and then the sock-socket connection is optimized and improved according to the analysis results.Firstly,the research status of connection mode between pier column and cap under the background of accelerated bridge construction is introduced.Based on the connection mode adopted in engineering background,three connection modes are selected for finite element analysis,and the mechanical properties of the pier are compared with the whole cast-inplace bridge pier.Midas FEA software was used to establish a finite element model to simulate the joint between the pier column and the cap.Under the premise of ensuring the basic consistency of the structure,the same vertical load and transverse load were applied to the top of the pier column respectively.The elastic and elastoplastic analysis was carried out to compare and study the compressive and flexural shear performance of different connection modes.At the same time,two groups of measured ground motion and seismic waves generated by SIMQRE GR program were used for time-history analysis,and displacement time-history diagrams were obtained to analyze the seismic performance of different connection modes.Secondly,according to the compression,flexure-shear and seismic analysis results of different connection modes,the pier-socket connection,whose mechanical properties have always been at a medium level,is optimized and innovated.Steel plates are anchored around the bottom of the pier column to enhance the connection between the pier column and the cap,so as to improve its integrity.The finite element model is also established for the connection mode,and the same load is applied to obtain the analysis results.Compared with the traditional socket connection,the effectiveness of the improved measure is expected to be verified.Finally,the finite element results of the five different connection modes are compared and analyzed comprehensively.The results show that the three connection modes of pier and cap with the characteristics of accelerated bridge construction can all meet the requirements of the code,and the mechanical properties are not different from the traditional cast-in-place method,so they can be applied to practical engineering.In addition,the optimization and improvement of the traditional socket connection method can effectively improve its mechanical properties.The research content of this paper has certain reference value in the engineering application and innovation research of the connection mode between pier column and cap.