【作者】 刘芳；

【导师】 占玉林；

【作者基本信息】 西南交通大学 ， 建筑与土木工程（专业学位）， 2020， 硕士

【摘要】 节段预制拼装桥梁具有诸多优势,如费用低、施工速度快、质量易控制、耐久性好、对周围交通影响小等,在桥梁工程广泛应用。接缝是节段预制拼装桥梁薄弱部位,对该类桥梁正常使用极限状态和承载力极限状态有重要影响,现有研究缺乏对重复荷载作用下接缝力学行为的研究。为研究重复荷载作用下键齿接缝的力学行,本文主要工作和结论如下:(1)设计制作了6组键齿接缝局部构件,并对其施加重复荷载进行试验研究。详细记录了试件破坏过程,探讨在重复荷载作用下,构件的极限荷载、裂缝发展、强度刚度退化以及荷载-位移曲线等力学性能;与同类型试验单调加载结果对比分析;对4种键齿类型单个小键齿、多个小键齿、大键齿及配筋大键齿)、掺钢纤维比例(0%、0.8%)进行参数分析。试验结果表明:重复加载极限承载力比单调加载降低接近30%,重复加载构件刚度低于单调加载;配筋大键齿构件的力学性能最优,多个小键齿构件力学性能与单键齿构件接近,接缝承载力键齿数目不成线性关系存在一定折减;试验构件重复荷载作用下强度退化不明显,掺钢纤维和在键齿内部配筋能够改善构件刚度退化,掺钢纤维构件的延性最优。(2)通过有限元软件ABAQUS对键齿接缝试验构件进行数值模拟,有限元结果与试验结果吻合良好,重点分析了键齿接缝的应力应变分布和发展规律。(3)通过有限元建模,探讨了不同侧向应力、接缝干接和胶接、荷载施加位置和更多键齿形状类型等关键因素对键齿接缝力学性能的影响。研究发现:键齿咬合深度对键齿接缝构件承载力的影响不大,但在键齿内部配筋能够大幅提升键齿性能;干接缝构件的应力和应变传递与胶接缝构件存在明显区别;随着侧向应力增加,键齿接缝构件的极限承载力提高;荷载施加位置改变造成键齿接缝从直剪受力状态变成弯剪共同作用。更多还原

【Abstract】 Segmental prefabricated bridge has many advantages,such as low cost,fast construction speed,easy quality control,good durability,little impact on the surrounding traffic,etc.,which are widely used in bridge engineering.The joint is the weak part of segmental prefabricated bridge,which has an important influence on the serviceability limit state and bearing capacity limit state of this kind of bridge.In order to study the mechanical behavior of key tooth joint under cyclic load,the main work and conclusions of this paper are as follows:(1)Six groups of key tooth joints are designed and manufactured,and the reciprocating load is applied to them.The failure process of the specimen is recorded in detail,and the mechanical properties of the component,such as the ultimate load,crack development,strength and stiffness degradation,and load displacement curve,are discussed under the action of cyclic load.The results are compared with the monotonic loading results of the same type of test.The ratio of single small key tooth,multiple small key teeth,large key teeth and reinforced large key teeth and steel fiber(0%,0.8%)of four key tooth types are analyzed Parameter analysis.The test results show that the ultimate bearing capacity of cyclic loading is reduced by nearly 30%compared with that of monotonic loading,and the rigidity of cyclic loading component is lower than that of monotonic loading;the mechanical performance of reinforced large key tooth component is the best,the mechanical performance of multiple small key tooth components is close to that of single key tooth component,and the number of key teeth in joint bearing capacity is not linearly reduced to some extent;the strength degradation of test component under the action of cyclic loading is unknown Obviously,adding steel fiber and reinforcing steel in the key teeth can improve the rigidity degradation of the component,and the ductility of the component with steel fiber is the best.(2)The finite element software ABAQUS is used to simulate the key tooth joint test component.The finite element results are in good agreement with the test results.The stress-strain distribution and development law of the key tooth joint are mainly analyzed.(3)Through the finite element modeling,the effects of different lateral stress,joint dry joint and adhesive joint,load application position and more key tooth shape types on the mechanical properties of key tooth joint are discussed.The results show that: the key tooth engagement depth has little effect on the bearing capacity of key tooth joint components,but the reinforcement inside the key tooth can significantly improve the key tooth performance;the stress and strain transfer of dry joint components is significantly different from that of glue joint components;with the increase of lateral stress,the ultimate bearing capacity of key tooth joint components increases;the change of load application position causes the key tooth joints to be in the form of direct shear stress The state becomes a combination of bending and shearing.更多还原