三向预应力混凝土斜拉桥箱梁裂缝研究  

Study on Construction Cracks in Box Girder of the Three-dimensionalPrestressed Concrete Cable-stayed Bridge

作　　者：孙文火 李平杰[1] SUN Wen-huo;LI Ping-jie(CCCC Fourth Harbor Engineering Institute Co.,Ltd.,Guangzhou 510230,China)

机构地区：[1]中交四航工程研究院有限公司,广州510230

出　　处：《科学技术与工程》2020年第17期7052-7058,共7页Science Technology and Engineering

基　　金：国家重点研发计划(2017YFC0805303);广州市珠江科技新星专项(201806010162)。

摘　　要：为分析混凝土水化热和三向预应力钢筋张拉顺序对斜拉桥预应力箱梁施工裂缝的影响,建立了嘉陵江大桥空间有限元实体模型,通过模拟现场实测温度场和选取3种不同的预应力钢筋张拉工序,分析水化热和预应力钢筋张拉顺序对箱梁顶板、底板和腹板受力特性的影响,并对比分析结果和实际裂缝情况。结果表明:水化热是嘉陵江大桥箱梁底板和腹板产生施工裂缝的一个重要原因;但是单纯的水化热不能使腹板产生裂缝。横向和竖向预应力钢筋滞后纵向1~2个节段张拉的施工工艺使得底板施工前期拉应力增长较快;且使得腹板在施工过程中拉应力变大。因而,预应力钢筋张拉顺序成为嘉陵江大桥箱梁底板和腹板产生施工裂缝的另一个重要原因,但是预应力钢筋张拉顺序对箱梁最终状态应力影响很小。In order to analyze the influence of hydration heat reaction of concrete and tension sequence of three-dimensional prestressed tendons on construction cracks of prestressed box girder of cable-stayed bridge,a spatial finite element solid model of Jialing River Bridge was established.Based on simulating the measured temperature field and choosing three different tension procedures of prestressed tendons,the influence of hydration heat reaction and tension sequence of prestressed tendons on the mechanical characteristics of the top,base and web plates of box girder was analyzed.And the analysis was compared with the actual cracks of Jialing River Bridge.The results show that the hydration heat reaction is an important reason for the construction cracks on the base plate and web plate of the Jialing River Bridge.However,single hydration heat reaction can not cause cracks in the web plate.The construction technology of transverse and vertical prestressed tendons tensioned later than longitudinal prestressed tendons for 1 or 2 segments makes the tensile stress of base plate increase rapidly in the early stage of construction,and makes the tensile stress of web plate larger in the construction.Therefore,the tension sequence of prestressed tendons is another important reason for the construction cracks on the base and web plates of the box girder of Jialing River Bridge.However,the tension sequence of prestressed tendons has little effect on the tensile stress of ultimate construction state of prestressed concrete box girder.

关 键 词：斜拉桥 预应力箱梁 张拉工艺 水化热 施工裂缝 

分 类 号：U445.47[建筑科学—桥梁与隧道工程]