栓钉连接件疲劳损伤导致的组合梁力学性能退化机理研究
发布时间：2018-10-13 10:41
【摘要】：钢-混凝土组合梁充分发挥材料性能,施工方便,已被广泛应用于桥梁工程中。栓钉连接件通常以集群的形式布置于钢梁上翼缘,界面剪力在栓钉连接件集群中分布不均匀。在疲劳荷载作用下,栓钉连接件的界面滑移量增加,抗剪刚度减小,从而引起界面剪力重分布。上述过程随疲劳荷载次数的增加而不断发展,具体表现为钢-混凝土界面滑移量不断增大,组合梁挠度不断增加。本文的主要研究内容和结论为:一、对三根钢-混凝土组合梁试件进行疲劳试验,研究剪力键剪切破坏为表征的钢-混凝土组合梁的疲劳破坏机理及疲劳损伤过程。试验得到以下结论:钢-混凝土组合梁的疲劳寿命对疲劳荷载相当敏感,疲劳荷载幅值及疲劳荷载峰值都会显著影响组合梁的疲劳寿命;根据组合梁的挠度及剪力键群的抗剪刚度演化规律,可以将剪力键剪切破坏为表征的钢-混凝土组合梁的疲劳损伤三个阶段;剪力键群的抗剪性能退化是与单个剪力键的疲劳损伤相耦合的动态过程;组合梁的挠度变化不一定能反映其内部损伤。二、考虑栓钉连接件的非线性荷载-滑移关系,基于受弯条件下简支组合梁的界面滑移量和荷载的协调方程,建立钢-混凝土组合梁界面"非连续传力"模型,并使用MATLAB编程求解栓钉连接件的滑移量和承担的剪力,计算结果与数值模型吻合良好。参数分析发现,增大界面抗剪刚度能够提高组合梁的刚度,但不能无限制提高。三、基于疲劳加载后栓钉连接件界面残余滑移量的发展,将疲劳荷载作用下栓钉连接件的抗剪刚度退化模型引入"非连续传力"模型中,研究疲劳荷载作用下,界面剪力在栓钉连接件集群中的重分布和组合梁刚度退化现象。分析表明,疲劳加载不仅使钢-混凝土界面剪力减小而且使其在栓钉连接件集群中分布更均匀;组合梁跨中挠度随疲劳加载的进行近似线性增长。
[Abstract]:Steel-concrete composite beam has been widely used in bridge engineering because of its material properties and convenient construction. Stud joints are usually arranged in clusters on the flange of steel beams, and the interfacial shear forces are distributed inhomogeneously in the cluster of bolt connectors. Under fatigue load, the interfacial slip of the stud joint increases and the shear stiffness decreases, which results in the redistribution of the interfacial shear force. The above process develops with the increase of fatigue load times, which is manifested by the increasing slip at the steel-concrete interface and the increasing deflection of composite beams. The main contents and conclusions of this paper are as follows: first, the fatigue failure mechanism and fatigue damage process of steel-concrete composite beams characterized by shear bond shear failure are studied. The results show that the fatigue life of steel-concrete composite beams is very sensitive to fatigue load, and the amplitude of fatigue load and the peak value of fatigue load will significantly affect the fatigue life of composite beams. According to the evolution law of deflection of composite beam and shear stiffness of shear bond group, the fatigue damage of steel-concrete composite beam can be characterized by shear bond shear failure. The degradation of shear behavior of the shear bond group is a dynamic process coupled with the fatigue damage of a single shear bond, and the deflection change of the composite beam may not necessarily reflect the internal damage. Secondly, considering the nonlinear load-slip relationship of stud connections, a discontinuous force transfer model at the interface of steel-concrete composite beams is established based on the equations of interface slip and load coordination of simply supported composite beams under bending conditions. The slippage and shear force of the stud joint are calculated by MATLAB program. The calculated results are in good agreement with the numerical model. Parameter analysis shows that the stiffness of composite beam can be improved by increasing the shear stiffness of interface, but it can not be increased without restriction. Thirdly, based on the development of residual slip at the interface of the stud joint after fatigue loading, the degradation model of shear stiffness is introduced into the "discontinuous force transfer" model under fatigue load. The redistribution of interfacial shear forces and stiffness degradation of composite beams in the cluster of stud connectors. The analysis shows that the fatigue loading not only reduces the shear force at the interface between steel and concrete but also makes it distribute more evenly in the cluster of stud joints, and the mid-span deflection of composite beam increases linearly with fatigue loading.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U441
本文编号：2268325
[Abstract]:Steel-concrete composite beam has been widely used in bridge engineering because of its material properties and convenient construction. Stud joints are usually arranged in clusters on the flange of steel beams, and the interfacial shear forces are distributed inhomogeneously in the cluster of bolt connectors. Under fatigue load, the interfacial slip of the stud joint increases and the shear stiffness decreases, which results in the redistribution of the interfacial shear force. The above process develops with the increase of fatigue load times, which is manifested by the increasing slip at the steel-concrete interface and the increasing deflection of composite beams. The main contents and conclusions of this paper are as follows: first, the fatigue failure mechanism and fatigue damage process of steel-concrete composite beams characterized by shear bond shear failure are studied. The results show that the fatigue life of steel-concrete composite beams is very sensitive to fatigue load, and the amplitude of fatigue load and the peak value of fatigue load will significantly affect the fatigue life of composite beams. According to the evolution law of deflection of composite beam and shear stiffness of shear bond group, the fatigue damage of steel-concrete composite beam can be characterized by shear bond shear failure. The degradation of shear behavior of the shear bond group is a dynamic process coupled with the fatigue damage of a single shear bond, and the deflection change of the composite beam may not necessarily reflect the internal damage. Secondly, considering the nonlinear load-slip relationship of stud connections, a discontinuous force transfer model at the interface of steel-concrete composite beams is established based on the equations of interface slip and load coordination of simply supported composite beams under bending conditions. The slippage and shear force of the stud joint are calculated by MATLAB program. The calculated results are in good agreement with the numerical model. Parameter analysis shows that the stiffness of composite beam can be improved by increasing the shear stiffness of interface, but it can not be increased without restriction. Thirdly, based on the development of residual slip at the interface of the stud joint after fatigue loading, the degradation model of shear stiffness is introduced into the "discontinuous force transfer" model under fatigue load. The redistribution of interfacial shear forces and stiffness degradation of composite beams in the cluster of stud connectors. The analysis shows that the fatigue loading not only reduces the shear force at the interface between steel and concrete but also makes it distribute more evenly in the cluster of stud joints, and the mid-span deflection of composite beam increases linearly with fatigue loading.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U441
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