斜裂纹对混凝土板抗弯承载力影响的试验研究  

Experimental Study of Influence of Oblique Cracks on Anti-Bending Performance of Concrete Slab

作　　者：位东升[1,2] 彭旭民[1,2] 邹力[1,2] 杨宏印[1,2] 

机构地区：[1]中铁大桥科学研究院有限公司,湖北武汉430034 [2]桥梁结构安全与健康湖北省重点实验室,湖北武汉430034

出　　处：《世界桥梁》2015年第6期68-72,共5页World Bridges

摘　　要：为了解斜裂纹对混凝土箱梁顶板抗弯承载能力的影响情况,采用局部结构缩尺模型试验方法,制作了长1 117mm、宽600mm、高140mm的箱梁顶板模型,通过弯剪加载实现混凝土箱梁顶板裂纹,对开裂试件进行化学灌浆,将试件分为完好、开裂、修补3种类型进行抗弯承载力试验。通过测试不同类型试件的加载力、位移和混凝土应变,分析斜裂纹对混凝土板的抗弯刚度及承载性能的影响,为该类病害处治提供试验依据。试验结果表明:3种试件竖向加载力与跨中位移、混凝土应变的变化关系基本一致,且极限承载力基本一致,斜裂纹对试件抗弯刚度、内力分布、抗弯极限承载力影响很小;3种试件的斜裂纹两侧未发现试件沿裂纹方向斜向错位现象,试件跨中底面横向开裂,斜裂纹对试件抗弯极限承载力的破坏形态影响很小。对此类病害,在桥面板承载能力验算满足规范要求的前提下,进行耐久性修复即可。To examine the influence of oblique cracks on the anti-bending performance of top slabs of concrete box girder,the scale-down model experimental method for local structures was employed and a top slab model of box girder with dimension of 1 117 mm by 600 mm,140mm high was prepared.Under the condition of applying bending and shearing loads,cracks were found on the top slabs of concrete box girder.Then the samples with cracks were chemically grouted,and the samples were classified into three groups of being undamaged,cracked and remedied in the anti-bending performance tests.By testing the loads applied to different types of samples and their displacement and the concrete strains,the influence of oblique cracks on the anti-bending stiffness and load bearing capacity of concrete slabs was analyzed,to provide testing references for deteriorations of such type.The results of the testing indicate that the variation of the vertical loading forces for the three groups of samples is approximate to the variation of midspan displacement and concrete strain,and the ultimate load bearing capacity is also the same,showing that oblique cracks have minimal influence on the anti-bending stiffness,internal force distribution and the antibending ultimate load bearing capacity of the samples.Along the two sides of oblique cracks of the three types of samples,no inclined dislocation along the direction of cracking was found.The underside of sample midspan transversely cracked,and oblique cracks have slight influence on the damaging modes of the anti-bending load bearing capacity of the samples.For such kind of deterioration,the remedy of durability can be carried out on the premise that the checking calculation of the load bearing capacity of the slabs meets the code requirements.

关 键 词：箱梁桥 混凝土箱梁 顶板 斜裂纹 抗弯承载力 模型试验 

分 类 号：U446[建筑科学—桥梁与隧道工程]