基于微膨胀混凝土的组合梁斜拉桥桥面抗裂性提升研究

Research on Enhancing Crack Resistance of Cable-stayed Bridge Decks with Composite Beams Based on Micro-expansion Concrete

针对组合梁斜拉桥在极端工况下混凝土易开裂的问题,以风荷桥为研究对象,采用干燥收缩试验结合ABAQUS有限元分析的方法,对膨胀剂掺量抑制干燥收缩的效果,以及混凝土桥面板在超载和混凝土收缩共同作用下的受力状态进行了分析,研究其在极端状况下的抗裂性能。结果表明:1)12%掺量的膨胀剂可降低22%的混凝土收缩;2)在超载1倍的情况下,不掺膨胀剂的混凝土开裂严重;3)掺入12%膨胀剂的混凝土仅在极少处产生开裂,满足实际使用需求。

To address the issue of concrete cracking under extreme conditions in composite girder cable-stayed bridges,this paper employs a combination of drying shrinkage experiments and Abaqus finite element analysis to investigate the effect of expansive agent dosage on mitigating drying shrinkage and the stress state of concrete bridge decks under the combined effect of overload and concrete shrinkage,and analyzes their crack resistance under extreme condition,using the wind-loaded bridge as the research subjects.The results indicate that:1)aA 12%content of expansive agent can reduce concrete shrinkage by 22%.Under the condition of twice the overload,concrete without expansive agent exhibits severe cracking;2)Concrete incorporating a 12%content of expansive agent only displays minimal cracking,which meets practical application requirements.