Seismic mitigation for bridges by the specific bearing with highly elastoplastic dissipaters is very important to ensure safety of superstructures exposed to earthquakes. To study the lateral vibration of the bridge bearing, a nonlinear dynamic model is developed while thoroughly considering highly nonlinear mechanical properties of the bearing in this article. The generalized-α method is specifically adapted to solve the nonlinear equations. Moreover, nonlinear behavior of the bearing is fully incorporated through direct path-following of the practical experimental hysteresis curve. The proposed method is validated through careful comparison between the dynamic simulation and the quasi-static experimental results. Mechanical responses of the bridge-pier system under earthquake excitations can be calculated in a more reliable manner. On this basis, a parametric optimization model involving several key parameters of the bearing-pier system is developed. The optimization problem is solved by the genetic algorithm as the searching tool. Numerical examples show that mechanical responses of the bridge-pier system subjected to the earthquake excitations can be effectively mitigated after parametric optimization. The extensive applicability of the proposed method is validated through finding the optimized parameters for the bearing when multiple different earthquakes are considered. Moreover, the accumulative energy absorption of the bearing is also considered to enhance the seismic performance of the bearing. This work provides a reliable way of dynamic performance prediction and seismic mitigation study of nonlinear bridge bearing under earthquake excitations given any complex experimental hysteresis curve.

中文翻译：

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桥梁支座非线性动力分析及基于遗传算法的减震优化

通过具有高弹塑性消散器的特定支座来减轻桥梁的地震对于确保上层建筑在地震中的安全非常重要。为了研究桥梁支座的横向振动，本文在充分考虑支座高度非线性力学特性的同时，建立了一个非线性动力学模型。广义α方法特别适用于求解非线性方程。此外，轴承的非线性行为是通过实际实验滞后曲线的直接路径跟踪完全纳入的。通过仔细比较动态模拟和准静态实验结果，验证了所提出的方法。桥墩系统在地震激励下的力学响应可以以更可靠的方式计算。以这个为基础，开发了一个涉及轴承墩系统几个关键参数的参数优化模型。优化问题是通过遗传算法作为搜索工具来解决的。数值算例表明，经过参数优化后，桥墩系统在地震激励作用下的力学响应可以得到有效缓解。当考虑多种不同的地震时，通过寻找轴承的优化参数验证了所提出方法的广泛适用性。此外，还考虑了轴承的累积吸能，以提高轴承的抗震性能。