某双幅双塔四索面矮塔斜拉桥混凝土箱梁局部早期收缩裂缝分析

Early shrinkage cracks of local concrete box girders at a double width-twin tower-four cable plane short tower cable stayed bridge

以盐城市某矮塔斜拉桥主梁0号块施工过程中顶板出现裂缝为工程背景,采用三维有限元模拟和理论分析相结合的方式,对影响箱梁0号块早期裂缝的浇筑间隔龄期、后浇层厚度和钢筋混凝土线膨胀系数进行了分析.研究结果表明:箱梁0号块整体收缩应力较小,但顶板与横隔板和腹板交界处出现应力集中;分层浇筑龄期、后浇层厚度和线膨胀系数对顶板收缩效应影响较大,施工时必须加以考虑.

Taking as the background arising of shrinkages during construction at upper plate of block 0 of the main beam for some short tower cable stayed bridge in Yancheng City, finite element analysis and theoretical a- nalysis were combined to study the effect of pouring interval age, last layer thickness and linear expansion factor of the reinforced concrete on the early shrinkage cracks of the block 0 of the box girders. Results show that global shrink stress of the block 0 of the box girders is relatively small, but stress concentration arises at the junction of upper plate, cross beam and web; pouring interval age, last layer thickness and linear expansion factor play im- portant roles in blockage effect of the uooer olate, which must be taken into consideration during construction.