钢管混凝土拱桥钢管初应力自动化监测与控制

为了解利用斜拉扣索调整钢管初应力的可行性,以六律邕江特大桥(计算跨径265 m的钢管混凝土拱桥)为背景,进行钢管混凝土拱桥钢管初应力自动化监测与控制技术研究。首先建立钢管初应力自动化监测系统,实现钢管初应力数据实时自动化采集;然后基于测试数据得到钢管初应力度并分析,确定最危险截面钢管初应力的发展历程;最后基于影响线原理,确定斜拉扣索预留位置,分析张拉斜拉扣索调整钢管初应力的效果。结果表明:大桥钢管初应力度最大为0.48(8号钢管拱顶位置),满足规范要求;钢管初应力度沿断面和拱轴线分布不均匀;钢管自重和混凝土灌注引起的钢管初应力占比约为6∶4;在混凝土灌注阶段,单组扣索能够调整约6 MPa的初应力,调整幅度约15%,验证了利用斜拉扣索对钢管初应力进行调整的有效性。

Automatic Monitoring and Control of Initial Stresses in Steel Tubes of Concrete-Filled Steel Tubular Arch Bridge

To verify the feasibility of using fastening stays to adjust the initial stresses in steel tubes,the Liulv Yijiang River Bridge,a concrete-filled steel tubular arch bridge with calculated span length of 265 m,is taken as a case in the study of automatic monitoring and control techniques for initial stresses in steel tubes of the concrete-filled steel tubular arch bridge.The automatic monitoring system for the initial stresses in the steel tubes was established to carry out real-time stress data collection,and based on which initial stress amplitude of the steel tubes was obtained and analyzed to determine the development of the initial stresses in the steel tubes with the most risky cross-section.In accordance with the influence line principle,the locations of the fastening stays were reserved,and the adjusting effect of initial stresses in steel tubes was analyzed.The results demonstrate that the maximum initial stress in steel tube is 0.48(steel tube No.8 at the crown of the steel tubular arch),meeting the code requirements.The initial stress/yield strength ratios of steel tubes are not uniform along the cross-section and arch axis.The ratio of initial stresses induced by self-weight and those induced by concrete pouring is 6∶4.In the concrete pouring stage,a single set of fastening stays can adjust roughly 6 MPa of initial stress,accounting for 15%,verifying the effectiveness of using fastening stays to adjust initial stress in steel tubes.