大跨铁路钢桁连续梁桥减隔震方案比较研究

为研究适用于大跨铁路钢桁连续梁桥的减隔震方案及合理优化参数,以一座全长504 m的三跨铁路钢桁连续梁特大桥为工程背景,使用非线性结构分析软件SAP2000建立有限元模型,采用快速非线性分析方法分析对比摩擦摆、阻尼器、速度锁定器等减隔震方案在各种装置参数下的减震效率。研究表明:由于大跨铁路钢桁连续梁桥墩身自振导致的地震力较大,摩擦摆方案内力减震效率一般,同时墩底内力对滑动面半径变化并不敏感,在选取滑动半径时应更多地考虑行车平顺性和梁端位移值的限制。速度锁定器会极大地增加此类桥梁地震输入能量,不适用于此类桥型。阻尼器方案对活动墩内力减震效果明显,但不能有效降低固定墩内力。摩擦摆支座附加阻尼器组合减震方案能有效控制此类桥梁的内力和位移响应。研究结论可为大跨度钢桁连续梁桥减隔震设计提供参考。

Comparative Study on Seismic Mitigation and Isolation Schemes fora Long-span Railway Steel Truss Continuous Beam Bridge

To investigate appropriate seismic mitigation and isolation schemes and rational optimal parameters for long-span railway steel truss continuous beam bridges, based on a three-span railway steel truss continuous beam bridge with a total length of 504 m, a finite element model was built with the non-linear finite element analysis program SAP2000. The damping efficiencies of different seismic mitigation and isolation devices, such as the friction pendulum, lock-up device, and damper, were compared by the fast non-linear analysis method. The results showed that, since the natural vibration of bridge piers may cause significant earthquake force, the scheme with a friction pendulum system does not show high efficiency. The lock-up device will greatly increase the seismic input energy of this kind of bridge, therefore, it is not recommended in this case; the scheme with a damper can significantly reduce the seismic response of piers with movable bearings; however, it cannot effectively reduce the seismic response of piers with a fixed bearing. A combination of the friction pendulum bearing and damper can effectively control the internal forces and the displacement response of this type of bridge. The conclusions can provide valuable reference for the seismic isolation of long-span railway steel truss continuous beam bridges.