逐跨施工混凝土连续箱梁考虑徐变的剪力滞效应研究  

Study of Shear Lag Effect in Continuous Concrete Box Beam Erected Span by Span Taking into Account of Creeping Effect

作　　者：方炜彬 蔺鹏臻[1] 

机构地区：[1]兰州交通大学甘肃省道路桥梁与地下工程重点实验室,甘肃兰州730070

出　　处：《世界桥梁》2015年第4期53-57,共5页World Bridges

基　　金：国家自然科学基金(51168030;51208242;51368031);甘肃省杰出青年基金(1210RJDA009);中国博士后科学基金(2012M521815)

摘　　要：为了解徐变对逐跨施工连续箱梁桥剪力滞效应的影响,基于能量变分法及混凝土徐变理论,建立2跨逐跨施工连续梁考虑剪力滞效应的混凝土徐变次内力计算公式,并以跨径为30m+30m的逐跨施工现浇箱梁桥为例进行计算。结果表明:对于存在施工过程体系转化的逐跨施工连续梁桥,徐变次内力增加了梁体在负弯矩区的弯矩、减小了梁体正弯矩区段的弯矩;考虑徐变效应后,截面的剪力滞效应有所减弱。算例结构中,支座负弯矩区最大剪力滞系数减小20.26%,跨中正弯矩区的剪力滞系数增加了2.1%。To examine the influence of creep on the shear lag effect of concrete box beam bridge constructed span by span,the calculation formula of the concrete creep secondary internal force of a two-span continuous beam erected span by span taking into consideration of the shear lag effect was established,based on the energy variational method and concrete creeping theory.And a cast-in-situ concrete box beam bridge erected span by span with span arrangement of 30m＋30m was cited as an example in the calculation.The results of the study show that for the continuous beam bridge erected span by span experiencing systematic transformation during the process of construction,the creep secondary internal force caused the increase of hogging moment,but the reduction of the positive bending moment.However,when the creeping effect was considered,the shear lag effect in the cross section showed the sign of abating.In the sample structure of the calculation,the maximum shear lag coefficient in the hogging moment zone of the bearings deceases by 20.26%,while the shear lag coefficient in the positive bending moment zone in the midspan increases by 2.1%.

关 键 词：连续梁桥 箱梁 徐变 剪力滞 逐跨施工 次应力 研究 

分 类 号：U441[建筑科学—桥梁与隧道工程] U445.4[交通运输工程—道路与铁道工程]