公路桥梁板式橡胶支座病害及应对策略研究

普通板式橡胶支座作为我国公路钢筋混凝土梁桥体系中的重要支承构件，其老化力学性能可影响局部及整体结构的服役安全性。因此，考虑橡胶材料老化、轴向压应力、支座几何构型等参数，研究老化橡胶支座在不同受力阶段的剪切性能。设计并进行了6个普通板式橡胶支座的剪切性能试验，对不同参数影响下支座的剪应变-剪应力曲线、剪切模量、水平位移-水平力及剪切刚度等参数进行对比分析。进一步应用有限元数值模拟方法，对老化支座的剪切性能进行参数分析，其有限元分析结果与试验结果进行对比。结果表明，橡胶等效老化年限小于20年，其橡胶老化对支座剪切性能的影响较小，则当橡胶等效老化时间大于50年，其剪切模量和剪切刚度增加，剪切变形能力降低，而橡胶老化对支座宏观剪切刚度的影响程度明显大于对材料剪切模量的影响。此外，支座剪应力-剪应变曲线、水平位移-水平力曲线及剪切刚度模拟结果随老化时间的变化规律与试验结果一致，且支座剪切性能随其剪切变形的增大，其模拟结果与试验结果之间差距逐渐降低。其中，当支座剪切变形达到100%时，支座剪切刚度模拟结果与试验结果最大相差20.4%，模拟结果与理论计算结果最大相差21.2%。鉴于实际桥梁工程中橡胶支座的老化受环境气候条件、车辆荷载或偶然荷载等的综合影响，其老化速度会有所加快，在进行老化支座剪切性能计算时应考虑其老化性能指标的取值。

Study on damage and dealing strategy of plate rubber bearing for the highway bridge

As an important supporting member, the ordinary plate rubber bearing is widely used in highway reinforced concrete girder bridges in China. The aging mechanical properties of rubber bearings affect the performance and safety of structures locally or entirely. Considering different parameters of aging rubber material, axial compressive stress and bearing geometry configuration, the shear performance of aging rubber bearing in different stress stages is studied. The shear performance tests of 6 ordinary plate rubber supports are designed and carried out, and the shear strain-stress curves, shear modulus, horizontal displacement-force relationship and shear stiffness are obtained. The finite element numerical simulation method is used to analyze the shear performance of the aging bearings, and then the finite element analysis results are compared with the test results. The results show that the effect of rubber aging on shear performance of the bearing is small when the equivalent aging age of rubber is less than 20 years; however, when the equivalent aging age of rubber is greater than 50, the shear modulus and shear stiffness increase, while the shear deformation ability decreases. The influence of rubber aging on macroscopic shear stiffness of the bearing is significantly greater than that on shear modulus. In addition, the simulated shear stress-shear strain curve, horizontal displacement-horizontal force curve and aging shear stiffness are consistent with the test results, and the difference between the simulation results and the test results decreases gradually with the increase of shear deformation. When the shear deformation reaches 100%, the simulated shear stiffness of the bearing is different from the test results by 20.4%, and different from the theoretical calculation results by 21.2%. The environmental conditions, vehicle load and accidental load may accelerate the aging speed of rubber bearing in actual bridges, and the aging effect should be taken into account in the calculation of shear performance.