钢-GFRP板条-UHPC组合桥面结构开裂及裂缝宽度计算方法研究  

Research on Flexural Test and Crack Width Calculation Methods for Steel-GFRP Strips-UHPC Composite Deck

作　　者：曾丹 曹磊 刘扬 张海萍 ZENG Dan;CAO Lei;LIU Yang;ZHANG Haiping(School of Civil Engineering,Hunan University of Technology,Zhuzhou 412007,China;School of Civil Engineering,Changsha University of Science and Technology,Changsha 410114,China)

机构地区：[1]湖南工业大学土木工程学院,湖南株洲412007 [2]长沙理工大学土木工程学院,湖南长沙410114

出　　处：《桥梁建设》2024年第5期94-101,共8页Bridge Construction

基　　金：国家自然科学基金项目(5217081979);湖南省自然科学基金项目(2024JJ7142);湖南省教育厅一般项目(22C0311)。

摘　　要：为研究钢-GFRP板条-UHPC组合桥面结构的裂缝发展和分布规律,设计3片GFRP-UHPC组合板和2片钢-GFRP板条-UHPC组合梁试件分别进行四点和三点弯曲试验,研究组合板和组合梁试件的破坏形态及机理;分析钢筋配筋率和钢纤维掺量对组合板和组合梁开裂性能的影响;分析现行规范中的最大裂缝宽度计算方法对该组合桥面结构的适用性;基于有滑移-无滑移统一理论,考虑混凝土保护层厚度对平均裂缝间距的影响和混凝土受拉贡献,推导适合钢-GFRP板条-UHPC组合桥面结构的最大裂缝宽度计算公式。结果表明:钢-GFRP板条-UHPC组合梁破坏时钢梁下翼缘发生明显的屈曲变形,裂缝主要分布在组合梁上表面跨中区域,GFRP-UHPC组合板破坏时板端出现相对分离,裂缝主要分布在纯弯段;提高受拉钢筋配筋率能提高组合桥面结构的极限抗弯承载力、抑制UHPC表面裂缝的发展、减小裂缝宽度和平均裂缝间距,而增加钢纤维掺量对组合桥面结构的极限抗弯承载力和抗弯刚度影响较小;采用现行规范计算的组合桥面结构最大裂缝宽度理论值偏小;提出的钢-GFRP板条-UHPC组合桥面结构的最大裂缝宽度计算公式计算值与试验值较吻合,具有较好的适用性。Three GFRP-UHPC composite deck panels and two steel-GFRP strips-UHPC composite beams were designed for four-point and three-point bending tests,respectively,to investigate the crack propagation and distribution in the steel-CFRP strips-UHPC composite deck.The study focuses include the failure modes and mechanism of the composite panels and beams,the influence of reinforcement ratio and steel fiber content on the cracking performance of the composite panels and beams,the applicability of the maximum crack width calculation methods suggested by the current codes for the composite deck,as well as the maximum crack width calculation equations suitable for the steel-GFRP strips-UHPC composite deck,following the unified theory of slip and considering the influence of the concrete cover thickness on the average crack spacing and the contribution to the tensile strength of concrete.It is demonstrated that when the steel-GFRP strips-UHPC composite beams failed,obvious flexural deformation was observed in the lower flanges of the steel girders,cracks were mainly in the midspan region of the upper surfaces of the composite beams,and the GFRP layer and UHPC layer of the GFRP-UHPC composite panel were disengaged at the ends,where the cracks were mainly in pure-bending moment zone.Improving the tensile reinforcement ratio led to the enhancement of the ultimate bending capacity,suppression of the propagation of the cracks in the surfaces of UHPC layer,reduction of crack width and average crack spacing,while the increase of steel fiber content exerted minor influence on the ultimate bending capacity and flexural stiffness.The maximum crack widths calculated using the equations given by current codes were smaller.The maximum crack widths calculated by the proposed equations in this paper agree well with the test results,justifying their applicability.

关 键 词：组合桥面结构 GFRP UHPC 受弯性能 裂缝宽度 模型试验 计算方法 

分 类 号：U443.32[建筑科学—桥梁与隧道工程] U441[交通运输工程—道路与铁道工程]