大跨径连续刚构桥不同龄期混凝土结合面收缩影响研究  

Analysis on Shrinkage Effects of Concrete Interfaces in Long-Span Continuous Rigid Frame Bridges

作　　者：石雪飞[1] 冯电视[1] 阮欣[1] 李小祥[1] 

机构地区：[1]同济大学桥梁工程系,上海200092

出　　处：《结构工程师》2008年第6期76-79,共4页Structural Engineers

摘　　要：以金塘大桥东通航孔216 m连续刚构为背景,分析不同龄期混凝土结合面的收缩应力分布特点。采用空间有限元与理论分析相结合的方式,比较不同分层浇筑时间间隔、配筋率、环境年平均相对湿度以及不同国家规范下的收缩效应,总结各因素对结合面收缩的影响。研究结果表明:由截面突变引起的结合面收缩效应明显;收缩应力随分层浇筑时间间隔和配筋率的增加而略微增大;环境湿度对结合面收缩的影响最为显著;对于大尺寸构件,采用AASHTO规范计算的结合面收缩应力水平明显高于JTGD62—2004,建议对JTG D62—2004中理论厚度取值设置上限。Based on Jintang Bridge＇ s east navigation channel, a 216-meter continuous rigid frame bridge, effects on shrinkage stress distribution characteristic at interfaces between concrete with different ages were analyzed. Combining spatial finite element method and theoretical way, shrinkage effects at interfaces under various factors were compared such as different casting time intervals, different reinforcement ratios, different average environmental relative humidity and effects under different codes. Results show that effects on shrinkage stress at interfaces caused by section property break are more obvious than that by different ages of concrete, and shrinkage stress increases with a small increment as casting time interval and reinforcement ratios increase, while humidity has the most significant influence on shrinkage effects. Results also show that shrinkage stress level calculated under AASHTO is much more reasonable than that under code JTG D62-- 2004 in concrete members with large thickness. Establishing a ceiling on theoretical thickness in JTG D62-- 2004 is advised.

关 键 词：大跨径连续刚构桥 结合面 收缩效应 混凝土龄期 规范 

分 类 号：U448.23[建筑科学—桥梁与隧道工程] U445.57[交通运输工程—道路与铁道工程]