Closed-form solution to thin-walled box girders considering effects of shear deformation and shear lag  

作　　者：周旺保 蒋丽忠 刘志杰 刘小洁 

机构地区：[1]School of Civil Engineering,Central South University [2]National Engineering Laboratory for High Speed Railway Construction(Central South University)

出　　处：《Journal of Central South University》2012年第9期2650-2655,共6页中南大学学报（英文版）

基　　金：Projects(51078355,50938008) supported by the National Natural Science Foundation of China;Project(CX2011B093) supported by the Doctoral Candidate Research Innovation Program of Hunan Province, China;Project(20117Q008) supported by the Basic Scientific Research Funds for Central Universities of China

摘　　要：Considering three longitudinal displacement functions and uniform axial displacement functions for shear lag effect and uniform axial deformation of thin-walled box girder with varying depths,a simple and efficient method with high precision to analyze the shear lag effect of thin-walled box girders was proposed.The governing differential equations and boundary conditions of the box girder under lateral loading were derived based on the energy-variational method,and closed-form solutions to stress and deflection corresponding to lateral loading were obtained.Analysis and calculations were carried out with respect to a trapezoidal box girder under concentrated loading or uniform loading and a rectangular box girder under concentrated loading.The analytical results were compared with numerical solutions derived according to the high order finite strip element method and the experimental results.The investigation shows that the closed-form solution is in good agreement with the numerical solutions derived according to the high order finite strip method and the experimental results,and has good stability.Because of the shear lag effect,the stress in cross-section centroid is no longer zero,thus it is not reasonable enough to assume that the strain in cross-section centroid is zero without considering uniform axial deformation.Considering three longitudinal displacement functions and uniform axial displacement functions for shear lag effect and uniform axial deformation of thin-walled box girder with varying depths, a simple and efficient method with high precision to analyze the shear lag effect of thin-walled box girders was proposed. The governing differential equations and boundary conditions of the box girder under lateral loading were derived based on the energy-variational method, and closed-form solutions to stress and deflection corresponding to lateral loading were obtained. Analysis and calculations were carried out with respect to a trapezoidal box girder under concentrated loading or uniform loading and a rectangular box girder under concentrated loading. The analytical results were compared with numerical solutions derived according to the high order finite strip element method and the experimental results. The investigation shows that the closed-form solution is in good agreement with the numerical solutions derived according to the high order finite strip method and the experimental results, and has good stability. Because of the shear lag effect, the stress in cross-section centroid is no longer zero, thus it is not reasonable enough to assume that the strain in cross-section centroid is zero without considering uniform axial deformation.

关 键 词：shear lag effect thin-walled box girder energy-variational method shear deformation closed-form solution 

分 类 号：U448.213[建筑科学—桥梁与隧道工程]