预应力混凝土现浇箱梁运营期腹板斜向裂缝损伤分析  

Analysis on Damage of Oblique Crack in Web of PC Cast-in-place Box Girder during Operation

作　　者：刘红义 张劲泉[3] 周建庭[1] 闫昕[2] LIU Hong-yi;ZHANG Jin-quan;ZHOU Jian-ting;YAN Xin(School of Civil Engineering,Chongqing Jiaotong University,Chongqing 400074,China;China-Road Transportation Verification&Inspection Hi-Tech Co.,Ltd.,Beijing 100088,China;Research Institute of Highway,Ministry of Transport,Beijing 100088,China)

机构地区：[1]重庆交通大学土木工程学院,重庆400074 [2]中路高科交通检测检验认证有限公司,北京100088 [3]交通运输部公路科学研究院,北京100088

出　　处：《公路交通科技》2022年第8期9-15,共7页Journal of Highway and Transportation Research and Development

基　　金：国家重点研发计划项目(2017YFE0103000,2018YFB1600305)。

摘　　要：为了研究某通车5 a大跨径预应力混凝土变截面现浇箱梁运营期腹板斜向裂缝产生的原因,对裂缝的时间和空间分布进行了详细检测和描述,裂缝主要分布在跨中附近,呈8字形分布,斜向裂缝逐年增多。首先分析了此类裂缝产生的常见原因和机理,重点从现行规范中的计算模式进行机理分析。然后建立了ABAQUS主桥实体有限元模型,在对该桥交通量、恒载、裂缝产生历史等充分调查的基础上,采用单因素分析和耦合因素分析方法,分析了箱梁竖向预应力损失、纵向预应力损失、超载等因素对箱梁腹板混凝土主拉应力的影响。结果表明:竖向预应力损失对腹板混凝土主拉应力影响不大,当纵向预应力损失21%或车辆超载45%时,腹板混凝土主拉应力超限;考虑竖向预应力损失40%、纵向预应力损失5%、超载40%等耦合因素,腹板混凝土主拉应力亦超限,耦合因素作用下有限元主拉应力超限位置与桥梁实际产生裂缝的位置具有一定的对应性;超载、纵向预应力损失等耦合因素是该桥腹板产生斜向裂缝的主要原因。研究成果为同类桥梁裂缝成因分析和维修处治提供工程参考。In order to study the causes of oblique cracks in the web of a 5-year long-span prestressed concrete cast-in-place box girder with variable cross-section,the temporal and spatial distribution of cracks is detected and described in detail.The cracks are mainly distributed near the mid-span,in a splay shape,and the oblique cracks are increasing year by year.First,the common causes and mechanism of such cracks are analyzed,focusing on the mechanism analysis by the calculation mode in the current specification.Then,the ABAQUS solid finite element model of the main bridge is established.On the basis of full investigation of the bridge’s traffic volume,dead load and crack generation history,by using the method of single factor analysis and coupled-factor analysis,the influences of vertical prestress loss,longitudinal prestress loss and overloading,etc.of box girder on the principal tensile stress of box girder web concrete are analyzed.The result shows that(1) the vertical prestress loss has little influence on the main tensile stress of the web concrete,when the longitudinal prestress loss is 21% or the overloading is 45%,the principal tensile stress of the web exceeds the limit;(2) considering the coupling factors of vertical prestress loss of 40%,longitudinal prestress loss of 5% and overloading of 40%,the principal tensile stress of the web also exceeds the limit,under the action of coupling factors,the overrun position of the finite element principal tensile stress has a certain correspondence with the actual position of the bridge crack;(3)The coupling factors such as overloading and longitudinal prestress loss are the main causes of oblique cracks in the web of the bridge.The research result provides an engineering reference for the cause analysis and maintenance of similar bridge cracks.

关 键 词：桥梁工程 斜向裂缝 数值模拟 箱梁 腹板 

分 类 号：TU375.1[建筑科学—结构工程]