应力集中致空心板L型裂缝研究  

STUDY ON L-TYPE CRACKS OF HOLLOW SLABS INDUCED BY STRESS CONCENTRATION

作　　者：彭卫兵[1] 史进 张武毅 张豪[1] 卢成原[1] PENG Wei-bing;SHI Jin;ZHANG Wu-yi;ZHANG Hao;LU Cheng-yuan(College of Civil Engineering and Architecture,Zhejiang University of Technology,Hangzhou,Zhejiang 310014,China;Zhejiang Traffic Detection Co.LTD,Hangzhou,Zhejiang 310012,China)

机构地区：[1]浙江工业大学建筑工程学院,浙江杭州310014 [2]浙江交科工程检测有限公司,浙江杭州311215

出　　处：《工程力学》2019年第11期112-120,共9页Engineering Mechanics

基　　金：国家自然科学基金项目(51778586);浙江省交通运输厅科技计划项目(2017003);浙江省交通运输厅科技计划项目(2018006)

摘　　要：由于中小跨径桥梁大多采用标准图纸进行设计,空心板上混凝土栏杆跨中分缝是标准图中常见的方案。然而,浙江台金高速杨司高架桥混凝土栏杆跨中分缝后,空心板边板跨中大规模出现单一L型裂缝,暗示栏杆分缝与空心板开裂密切相关。该研究经过现场调研,系统搜集整理了事故桥的图纸、施工、材料及现场开裂信息,通过基于ABAQUS建立弹性和混凝土塑性损伤的事故桥的有限元模型,分析了新型L型裂缝的产生机理。研究结果表明:1)当栏杆和空心板固结时,栏杆分缝将引起刚度突变,导致应力集中,诱发出现穿过传统中和轴的L型裂缝;2)随着跨中空心板上栏杆预留缝宽度的减小和深度的增大,边板跨中底部应力逐渐增加;3)无论是弹性模型还是塑性损伤模型,不合理的分缝引起应力集中的趋势一致。该文的研究发现将改变量大、面广的空心板栏杆分缝传统方案,提升空心板使用性能。Normally small and medium span bridges are designed using standard drawings. In particular, the mid-span parting-line of concrete safety barrier on hollow slabs is a common design in standard drawings. However, large-scale L-type cracks appeared in the mid-span of side girder of Yangsi viaduct on Taijin Expressway because of the mid-span concrete safety barrier parting-line on hollow slabs, suggesting that the mid-span concrete safety barrier parting-line is related to the cracks. Site investigation was carried out and information on the bridge’s drawings, construction, materials and cracking was collected. Elastic and plastic damage finite element models were established by using ABAQUS to analyze the cause of L-type cracks. The results demonstrated that: 1) When the safety barrier and hollow slabs were consolidated, the safety barrier parting-line caused a sudden change in stiffness, resulting in stress concentration and subsequently L-type cracks through the traditional neutral axis;2) With the decrease in the parting-line’s width and the increase in the parting-line’s depth, the stress at the mid-span bottom of the side girder gradually increased;3) Regardless of the elastic model or the plastic damage model, the trend of stress concentration induced by improper mid-span concrete safety barrier was consistent. The findings of this study are expected to modify the traditional scheme of concrete safety barrier parting-line and improve the performance of hollow slabs.

关 键 词：空心板 L型裂缝 混凝土护栏 分缝 应力集中 

分 类 号：U443.5[建筑科学—桥梁与隧道工程]