摘要
针对实际工程中存在的方形混凝土桥墩易于开裂的问题,以一典型公路桥为背景,对其存在的裂缝形态进行了现场调查及统计分析,依据裂缝特征及环境条件,初步判定为温度效应引起的结构裂缝.进一步用数值仿真方法,对方型桥墩从混凝土浇筑开始到成型1年后的水化热效应、日温度变化效应、季节温度变化效应以及温度骤降进行了温度场、应力场的历时变化模拟,并具体就桥墩混凝土材料、施工养护及设计方案进行参数分析,对温度裂缝控制对策进行了探究.研究结果表明;混凝土水化热及温度骤降是引起方形桥墩竖向裂缝的主要原因;从设计角度,桥墩以圆截面为佳,其截面尺寸不宜超过1.9m2;从施工角度,水泥质量浓度控制在200～350kg/m3,并尽量选取矿渣325或矿渣275水泥,入模温度以5～15℃为宜,且立模养护时间以3d为适;对成型桥墩可选择传热系数不超过4.5W/(m2.K)的保温材料覆加于其表面.
The quadrate concrete piers＇ crack analysis of highway bridge was done in order to research into the causations and effective treatments of common piers＇ cracks in bridge engineering. According to the crack＇s distributing pattern and shape feature, what the pier was crazed by temperature effect is taken for the real reason. The finite element analysis software was employed to emulate the possible temperature effect during these piers＇ first year after construction, in instance of hydration heat effect, solar temperature effect, seasonal temperature effect and temperature drop. Followed parameters analysis supplies some references for tlae piers＇ construction and design. Analysis results indicate that： Hydration heat effect and temperature drop are concluded as main crack causes. Circle-section pier is benefit for temperature effect control, and whose section area is inadvisable bigger than 1.9 m^2. In piers＇ construction, the cement content is suggested as 200 to 350 kg/m^3 and slag cement 325 or 275 is the priority; 5-15 ℃ is suitable as casting temperature; The curing period is suggested as 3 days. Protective coating can perform well after temperature drop, whose thermal conductivity coefficient should be 4.5 W/（m^2 · K） at most.
出处
《浙江大学学报（工学版）》
EI
CAS
CSCD
北大核心
2010年第9期1738-1745,共8页
Journal of Zhejiang University：Engineering Science
关键词
混凝土桥墩
裂缝分析
有限元
水化热效应
温度效应
bridge engineering
concrete pier
crack analysis
finite element
hydration heat effect
temperature effect
