摘要
在役混凝土桥梁经过长时间的服役工作,其结构的完整性产生改变以及材料性能发生实质性退化,需要对桥梁结构进行评估分析。选取一座在役混凝土桥梁,通过有限元技术建立桥梁模型,采用离散模型对裂缝进行建模,做受弯模拟进行计算分析;根据受力裂缝类型以及分布位置,分别研究存在不同形态下的弯曲裂缝与剪切裂缝对混凝土桥梁结构的破坏行为以及承载力退化的影响。研究发现存在弯曲裂缝对桥梁结构的破坏行为影响较小,在不同裂缝高度与宽度下荷载-位移曲线变化较小,结构破坏前底部纵筋与开裂处箍筋受力达到屈服状态,裂缝分布均匀且从加载点向两端高度递减;剪切裂缝高度对桥梁结构的破坏行为有着显著的影响,在剪切裂缝高度较高时,荷载-位移曲线发生明显的下降,剪切裂缝宽度对桥梁结构承载力影响较小,不同宽度下荷载-位移曲线基本保持一致,结构破坏前底部纵筋并没有达到屈服状态,在剪切裂缝处开裂贯穿梁体导致结构破坏而梁体其余部分开裂高度相对较低。考虑到开裂桥梁结构产生的变形由两部分组成,由此引入结构刚度折减计算公式,依据相关标准推导出剩余承载力计算公式,并对选取桥梁进行承载力验算,偏差在5%之内。
After the long-term service,concrete bridges undergo structural integrity variation and substantial degradation of material properties.The bridge structure needs to be evaluated and analyzed.This study selected an in-service concrete bridge and employed finite element technology to establish the bridge model.The discrete model was used for crack modeling,and the flexural simulation was conducted for analysis and calculation.Based on the types and distribution of stress-induced cracks,the study investigated the influence of flexural and shear cracks in different morphologies on the failure behavior and degradation of concrete bridge structure bearing capacity.The result indicates that the presence of flexural cracks has little effect on the structural failure behavior of bridge.With different crack heights and widths,the load-displacement curve shows minimal variation.Before structural failure,the bottom longitudinal reinforcement and the stirrups at crack location reach the yield state.The cracks distribute uniformly and decrease from the loading point to the height of both ends.The height of shear cracks significantly affects the failure behavior of bridge structure.When the height of shear fracture is high,the load-displacement curve decreases obviously.The shear cracks’width has little effect on the bearing capacity of bridge structure.The load-displacement curves remain essentially consistent with different widths.Before structural failure,the bottom longitudinal reinforcement does not reach the yield state.The cracks at the shear crack location penetrating through beam lead to structural failure,while the rest of beam has a relatively lower height of cracking.The formula for structural stiffness reduction is introduced considering the deformation of cracked bridge structure consists of two parts.Based on the relevant standard,the formula for residual bearing capacity calculation is derived,and the selected bridge bearing capacity is verified with the deviation within 5%.
作者
马智嵘
邬晓光
常兴科
黄江
MA Zhi-rong;WU Xiao-guang;CHANG Xing-ke;HUANG Jiang(School of Highway,Chang’an University,Xi’an,Shaanxi 710064,China;Shanxi Provincial Expressway Group Co.,Ltd.,Taiyuan,Shanxi 030031,China;Shanxi Provincial Highway Bureau,Taiyuan,Shanxi 030006,China)
出处
《公路交通科技》
CAS
CSCD
北大核心
2024年第8期154-161,共8页
Journal of Highway and Transportation Research and Development
基金
山西交通控股集团有限公司科技项目(2022-JKKJ-16)
山西省交通运输厅项目(2022-123)。
关键词
桥梁工程
承载力退化
结构破坏
刚度折减
剩余承载力计算
bridge engineering
bearing capacity degradation
structural failure
stiffness reduction
residual bearing capacity calculation
