通车条件下抗扰动混凝土拼接养护期微观损伤研究  

Study on Microscopic Damage of Anti-disturbance Concrete during Splicing Maintenance under Normal Traffic Condition

作　　者：苏文豪 朱超宇 宋军[2] 陈搏 SU Wen-hao;ZHU Chao-yu;SONG Jun;CHEN Bo(Guangdong Provincial Freeway Co.,Ltd.,Guangzhou Guangdong 510001,China;College of Civil Engineering,Tongji University,Shanghai 200092,China;Xiaoning Institute of Roadway Engineering,Guangzhou Guangdong 510641,China)

机构地区：[1]广东省高速公路有限公司,广东广州510001 [2]同济大学土木工程学院,上海200092 [3]广州肖宁道路工程技术研究事务所有限公司,广东广州510641

出　　处：《公路交通科技》2024年第1期90-97,共8页Journal of Highway and Transportation Research and Development

基　　金：广东省省级科技计划项目(2021B1111610002);广东省高速公路改扩建关键技术研究课题(MJKJ-SY-001)。

摘　　要：扩建桥梁的拼宽连接需要在通车条件下进行,对于仍在养护期内的抗扰砼拼接带性能可能会产生一定影响。通过现场检测仅能发现拼接带的宏观损伤,行车振动引起的拼接带内部微观损伤难以观测。基于有限元仿真分析、CT扫描技术,对拼宽桥梁拼接带的受力分布情况及实际损伤状况进行了研究。首先,利用ANSYS有限元软件建立拼宽桥梁实桥仿真分析模型,明确不同工况下拼宽桥梁拼接带的受力特点。其次,基于仿真模拟结果选取拼接带关键位置,获取拼接带跨中、四分点截面的接缝中心线及交界面关键位置处的抗扰砼芯样,进行抗扰砼芯样的外观观测。最后,利用CT扫描技术获取芯样断层扫描观察图像,并基于获取的扫描数据对芯样内部结构进行了三维重构,分析拼接带抗扰砼在受扰振动后的集料分布情况、裂缝扩展情况。结果表明:各工况下拼接带抗扰砼横向受力主要以顶部受压、底部受拉为主,仅支点位置附近存在偏压趋势,且均能满足抗扰砼材料强度要求;对于拼接带中心线位置处的芯样,芯样内部无明显裂纹损伤,芯样内部骨料、纤维分布均匀,拼接带顶部钢纤维多水平分布、底部纤维多斜向分布;对于交界面位置处的芯样,在芯样顶部交界面存在一定的微裂隙,裂隙深度小于1 cm,该微裂隙对拼接带界面性能影响较小,近交界面位置处,钢纤维存在一定下沉趋势且纤维多呈斜向分布;在通车条件下拼接桥梁,车桥耦合振动将造成拼接带内钢纤维发生取向、甚至下沉的影响,减小拼接带抗扰砼抗拉性能。The connection of widening bridge needs to be carried out under the normal traffic condition.For the anti-disturbance concrete of the splicing zone,it is still in the concrete curing period,and its performance may be affected.Through on-site detection,only the macroscopic damage of the splicing zone can be found.The microscopic damage inside the concrete of splicing zone caused by vehicle-bridge coupling vibration is difficult to observe.Based on finite element simulation analysis and CT scanning technology,the stress distribution and actual damage of the concrete splicing zone are studied.Firstly,the simulation analysis model of widening bridge is established by the ANSYS finite element software.Based on different working conditions,the stress characteristics of widening bridge splicing zone are clarified.Secondly,the key positions of the splicing zone are selected based on the simulation results.The mid-span and quarter-point sections of bridge are selected as the key section.The concrete core samples at the joint center line and interface from the key section are obtained.The appearance of the concrete core samples is observed as well.Finally,the CT scanning technology is applied to obtain the tomography observation image of core sample.Based on the obtained scanning data,the internal structure of the core sample is reconstructed in three dimensions.The aggregate distribution and crack propagation of the splicing concrete after disturbed vibration are analyzed.The result shows that(1)The lateral force of the anti-disturbance concrete in splicing zone under various working conditions are mainly compression at the top of the joint and tension at the bottom of the joint.Only near the supporting point position,the stress characteristics of the joint section have the tendency of eccentric compression.The transverse force of splicing zone can meet the strength limit of antidisturbance concrete material.(2)For the core sample from the center line of the splicing zone,there is no obvious crack inside the core sample,a

关 键 词：桥梁工程 微观损伤 CT扫描 抗扰动混凝土 拼宽桥梁 不中断交通拼接 

分 类 号：U441.2[建筑科学—桥梁与隧道工程] U444[交通运输工程—道路与铁道工程]