水化热对早龄期连续刚构箱梁开裂的影响  

Influence of Hydration Heat on the Cracking of Continuous Rigid Frame Box Girder at Early Ages

作　　者：陈金义 李扬 廖伟华 杨高飞 CHEN Jin-yi;LI Yang;LIAO Wei-hua;YANG Gao-fei(Shanghai Municipal Engineering Design Institute Group 10th Design Institute Co.Ltd.,Lanzhou 730000,China;Shanghai Municipal Engineering Design Institute(Group)Co.Ltd.,Shanghai 200092,China)

机构地区：[1]上海市政工程设计研究总院集团第十市政设计院有限公司,兰州市730000 [2]上海市政工程设计研究总院(集团)有限公司,上海市200092

出　　处：《公路》2023年第1期106-110,共5页Highway

基　　金：国家自然科学基金项目,项目编号51878488;甘肃省科技计划资助项目,项目编号19YF3GA004。

摘　　要：针对某大跨径预应力混凝土连续刚构箱梁早龄期腹板裂缝问题,对裂缝进行了现场详细的调查统计,建立了混凝土箱梁开裂节段水化热分析模型。分析结果表明,混凝土早龄期水化热产生的温度场未完全稳定,主拉应力呈现先快速增长后缓慢衰减的趋势;在早龄期张拉纵向预应力钢束后,在温度与预应力作用耦合下,混凝土箱梁腹板中产生了较大的主拉应力,从而导致腹板开裂。本研究结果可为研究大跨径连续刚构箱梁水化热效应和确定腹板钢束张拉时机提供参考。In this paper, studies are carried out in regard with the actual problem of web cracks in a large-span prestressed concrete continuous rigid frame box girder at early age. Detailed investigation and statistics of the on-site cracks are conducted, and the hydration heat analysis model of the cracked section of the concrete box girder is established. The analysis results show that the temperature field generated by the heat of hydration in the early age of concrete is not completely stable, and the main tensile stress shows a rapid growth first and then a slow decay trend. After the longitudinal prestressed steel strand is stretched at the early age, under the coupling of temperature and prestressing, a large principal tensile stress is generated in the web of the concrete box girder, which leads to the cracking of the web. The results of this study can provide some reference for studying the effect of heat of hydration of a large-span continuous rigid frame box girder and the timing of the web steel bundle tensioning.

关 键 词：桥梁工程 连续刚构 水化热 箱梁开裂 有限元分析 

分 类 号：U448.23[建筑科学—桥梁与隧道工程] U441.5[交通运输工程—道路与铁道工程]