组合梁斜拉桥施工阶段桥面板防开裂技术研究  

Study on Anti-cracking Technology for Deck of Composite Girder Cable-stayed Bridge in Construction Stage

作　　者：阮映辉 孙立鹏 杨岳华 马印平[2] RUAN Ying-hui;SUN Li-peng;YANG Yue-hua;MA Yin-ping(Zhejiang Taizhou Coastal Expressway Co.,Ltd.,Taizhou Zhejiang 318001,China;School of Highway,Chang'an University,Xi'an Shaanxi 710064,China;ZTIG Expressway Construction Management Co.,Ltd.,Hangzhou Zhejiang 310000,China)

机构地区：[1]浙江台州市沿海高速公路有限公司,浙江台州318001 [2]长安大学公路学院,陕西西安710064 [3]浙江交投高速公路建设管理有限公司,浙江杭州310000

出　　处：《公路交通科技》2022年第11期106-114,共9页Journal of Highway and Transportation Research and Development

基　　金：浙江省交通运输厅科技项目(2020030)。

摘　　要：为了改善组合梁斜拉桥在施工过程中混凝土桥面板的受力状态,解决拉索锚固区桥面板开裂问题,以某双塔钢箱组合梁斜拉桥为工程背景,采用ABAQUS有限元软件建立了部分悬拼梁段的精细化混合单元有限元模型,对组合梁悬臂拼装的全过程进行了数值模拟。分析了混凝土桥面板在施工阶段的受力特点、开裂风险高的位置及开裂原因,提出了“滞后浇注锚固区局部湿接缝”的技术措施,并研究了该措施对拉索锚固区混凝土桥面板及钢梁受力的影响。结果表明:采用节段整体吊装法施工的组合梁斜拉桥,当每2个节段浇注一次桥面板湿接缝时,在新梁段起吊之前,先将待浇湿接缝处的纵向受力钢筋进行可靠连接,使其与钢梁共同承受荷载,可避免湿接缝附近混凝土桥面板的开裂;导致拉索锚固区桥面板斜向开裂的原因有两点:一是悬臂施工在拉索锚固区产生了较大的负弯矩;二是斜拉索的水平力传递给主梁时,以一定的角度从拉索锚固区向桥面板中部扩散,轴力扩散最快的区域面内剪应力最大,该剪应力导致拉索锚固区附近的桥面板出现较大的主拉应力;“滞后浇注锚固区局部湿接缝”的技术措施可有效减小施工阶段拉索锚固区桥面板主拉应力峰值,避免桥面板开裂,并且对钢梁的受力影响较小,可以保证施工安全。To improve the stress state of concrete deck on composite girder cable-stayed bridge in construction stage and solve the problem of cracking on bridge deck in the cable anchorage area,on the background of a bridge,the elaborate hybrid finite element model of several cantilever girder segments is established by using finite element software ABAQUS.The stress characteristics and cracking reasons of the concrete bridge deck during construction are analyzed,and the technical measure of“delayed pouring of local wet joints in the anchorage area”is put forward.The influence of this measure on stresses of concrete deck and steel girder at cable anchorage zone are analyzed.The result indicates that(1)Before hoisting the newgirder segment,the longitudinal stress steel bars at the wet joint to be poured should be connected to bear the load together with the steel girder,which can avoid the cracking of the concrete deck near the wet joint.(2)There are 2 reasons for the diagonal cracking of the bridge deck in the cable anchorage area.One is that the overall precast segment of the composite beam is too heavy,and a large negative bending moment is generated in the cable anchorage area during hoisting.The other is that when the horizontal force of the stay cable is transmitted to the bridge deck,a large shear stress is formed in the deck near the cable anchorage area.(3)The technical measure of“delayed pouring of local wet joints in the anchorage area”can effectively reduce the principal tensile stress peak value of the bridge deck in the cable anchorage area during construction,avoid cracking of the bridge deck,and has little influence on the stress of the steel girder,which can ensure the construction safety.

关 键 词：桥梁工程 防开裂技术 有限元法 斜拉桥 组合梁 悬臂拼装 

分 类 号：U445.4[建筑科学—桥梁与隧道工程]