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桥梁伸缩装置影响桥梁结构使用寿命和行车安全。该文以某大桥伸缩装置破损更换选型为例,应用Midas有限元软件建立桥梁模型,模拟计算温度变化、混凝土收缩徐变、汽车制动力、车辆荷载、纵向坡度等因素对梁端位移影响。结果表明:伸缩量可由体系温差、混凝土收缩徐变和汽车制动力三者引起的梁端位移之和乘以相应的增大系数求得;汽车制动力主要影响主梁顺桥向位移,按规范计算的伸缩量仅是板式橡胶支座剪切变形引起的梁端位移,应加上桥墩弯曲变形引起的梁端位移,特别是桥墩较高,刚度比较小的桥梁;对运营10年以上桥梁,可不考虑混凝土收缩徐变对伸缩装置的影响。理论计算和有限元分析表明:该桥引桥建成时安装美国万宝系列SD-160型伸缩装置不合理,伸缩量应满足ΔL≥379.2mm;运营15年后,伸缩量应满足ΔL≥292.2mm,建议选择320型模数式伸缩装置。
Bridge expansion device affect the service life of bridge structure and traffic safety. Taking the replacement of a telescopic telescopic device as an example, a bridge model is established by using Midas finite element software to simulate the influence of temperature variation, concrete shrinkage and creep, vehicle braking force, vehicle load and longitudinal gradient on the displacement of beam ends. The results show that the amount of expansion and contraction can be obtained by the sum of the displacement of the beam end due to the temperature difference of the system, the shrinkage and creep of the concrete and the braking force of the vehicle multiplied by the corresponding increasing factor. The braking force of the vehicle mainly affects the displacement of the main beam along the bridge, The amount of expansion and contraction is only the displacement of the beam end caused by the shear deformation of the plate rubber bearing. The displacement of the beam end due to the bending deformation of the bridge piers should be added, especially for the bridge with relatively high and less rigid piers. Influence of Concrete Shrinkage and Creep on Telescopic Device. Theoretical calculation and finite element analysis show that it is not reasonable to install American Wanbao SD-160 telescopic device when the bridge is completed, and the expansion and contraction should satisfy ΔL≥379.2mm. After 15 years of operation, the expansion and contraction should meet ΔL≥292.2mm. Select 320 modular retractable device.