悬臂施工过程中箱梁水化热温度场研究  

Analysis to the Temperature Field of Box Girder Caused by Cement Hydration Heat During Cantilever Construction

作　　者：刘芳平[1] 周建庭[2] 宋军[2] 吴恒[2] 

机构地区：[1]重庆三峡学院土木工程学院,重庆404100 [2]重庆交通大学土木建筑学院,重庆400074

出　　处：《施工技术》2013年第11期97-100,共4页Construction Technology

基　　金：重庆市重大科技攻关资助项目(CSTC2009AB6149);三峡库区库岸地质灾害预防与科研创新团队资助项目

摘　　要：结合混凝土连续箱梁桥工程实例,对悬臂施工中箱梁混凝土水化热温度场基于热量传导理论用Midas/FEA建立有限元模型进行了数值计算,并与箱梁水化热温度现场实测数据进行对比。结果表明,箱梁底板、腹板温度随水化热发展,都经历了较快温升阶段,到达极值,然后进入缓慢温降阶段,具有水化热温度变化的一般性规律;混凝土浇筑后构件最大内外温差与其厚度和表面边界条件有关,构件厚度越大,表面散热越好,能达到的最大内外温差也越大;在目前混凝土水化热不能有效消除、水化热温变应力还不能单独监测情况下,施工中可采取措施增加箱梁与外界环境对流,降低结构散热速度,从而预防温度裂缝产生。Using the engineering project of a continuous concrete box girder as an example,this paper investigates the temperature field caused by cement hydration heat in box girders during cantilever construction.Based on the theory of heat transfer,a finite element analysis model was built with Midas/FEA and the temperature field was calculated.The finite element analysis results were compared against the site measurements.The results show that,with the development of the hydration process,the temperatures of the bottom slab and the webs experienced a phase of rapid rise,and a slow cooling phase followed after they reached the maximum values.After pouring,the maximum temperature difference between the interior and exterior locations was affected by the thickness of the member and the surface conditions.The thicker is the member and the better is the heat dissipation behaviour of the surface,the higher will be the temperature difference between the inside and outside locations.Currently,the hydration heat cannot be effectively eliminated,and temperature stress cannot be independently monitored.In this condition,measures can be taken to increase the convection between the girder and the environment,thus reducing the heat dissipation rate and preventing the occurrence of temperature cracks.

关 键 词：桥梁工程 混凝土箱梁桥 水化热 温度场 有限元分析 现场测试 

分 类 号：U441.5[建筑科学—桥梁与隧道工程]