混凝土箱梁分层浇筑水化热实测与模拟分析  

Measurement and Simulation Analysis of Hydration Heat of Layered Pouring Concrete Box Girder

作　　者：邹惠琼 白洪涛 李梅 ZOU Hui-qiong;BAI Hong-tao;LI Mei(Yunnan Transportation Planning and Design Institute Co.,Ltd.,Kunming 650011,China)

机构地区：[1]云南省交通规划设计研究院有限公司,云南昆明650011

出　　处：《混凝土与水泥制品》2022年第6期77-81,共5页China Concrete and Cement Products

基　　金：云南省交通运输厅科技创新及示范项目(云交科教便[2020]104号);云南省交通规划设计研究院有限公司自立科技项目(ZL-2020-01)。

摘　　要：为探究混凝土箱梁在分层浇筑施工过程中水化热温度的发展规律及其温度应力,对某主跨230 m的大跨度预应力混凝土箱梁桥零号块水化热进行了连续观测,并基于观测结果和有限元数值模拟计算,分析了零号块水化过程中底板、腹板和横隔板的温度应力发展规律;同时,讨论了分层浇筑和整体浇筑两种不同施工方案对零号块水化热温度应力分布的影响,研究了拆模时间对结构内外温度的影响程度。结果表明:内外温差在结构内部产生的温度应力超过了材料的抗拉强度,从而导致了温度裂缝的产生;采用分层浇筑施工的零号块将在上下层混凝土交界面附近形成一条拉应力带;过早拆模会使混凝土内外温差迅速扩大,而养护4 d后拆模混凝土内外温差相对较小,建议零号块拆模前养护时间不宜少于4 d。In order to explore the development law of concrete hydration heat temperature of box girder by distinct-layer casting and accurately calculate the temperature stress,the concrete hydration heat in the No.0 block of box girder of a long span(230 m)PC continuous bridge was observed continuously.Based on the field test results and the numerical simulation calculation by FEA,the temperature stress development law of the bottom plate,web and diaphragm were analyzed.Meanwhile,the influence of the construction scheme on the hydration heat temperature stress of the No.0 block of box girder was discussed and the influence of the form removal time on temperature difference was researched.The results show that the excessive temperature difference can cause the excessive temperature stress and the temperature cracks.Besides,the tensile stress field can be formed near the interface between the top and the bottom concrete in the No.0 block of box girder by distinct-layer casting.The research results also show that the form removal time should not be less than 4 days to prevent temperature cracks.

关 键 词：分层浇筑 零号块 水化热 温度应力 拆模时间 

分 类 号：TU528[建筑科学—建筑技术科学]