Owing to the increasing span of pedestrian bridges and the use of new lightweight and high-strength materials, the natural frequency of pedestrian bridges has been reduced significantly. A pedestrian bridge experiences a wide range of vibrations while being walked on by large crowds. This type of vibration affects the comfort of people walking on the footbridge and also the safety of the footbridge. This paper proposes a dynamic design method that is suitable for long-span composite footbridges. The footbridge considered in this study comprises a composite steel box girder with self-anchored suspensions and has a main span of 70.5m. The dynamic characteristics of the long-span footbridge were analyzed using the finite element model, and the first 10 frequencies and mode shapes were obtained. Based on the global analysis of comfort standards, the comfort index for a practical evaluation was proposed, along with the walking excitation load. Meanwhile, a tuned mass damper (TMD) was adopted for the vibration reduction of the long-span footbridge constructed using a composite box girder with self-anchored suspensions in order to determine its applicability. Furthermore, the TMD layout was optimized using a GA. The results demonstrated that the proposed method can provide a theoretical basis and reference for the dynamic design of long-span composite pedestrian bridges.

中文翻译：

---

自锚式悬挂复合钢箱梁行人天桥采用调谐质量阻尼器减振

由于人行天桥跨度的增加和新型轻质高强材料的使用，人行天桥的固有频率显着降低。人行天桥在被大量人群行走时会经历广泛的振动。这种振动影响人行天桥行走的舒适度，也影响人行天桥的安全。本文提出了一种适用于大跨度复合材料人行桥的动态设计方法。本研究中考虑的人行桥包括一个带有自锚式悬挂的复合钢箱梁，主跨度为 70.5米。采用有限元模型分析了大跨度人行桥的动力特性，得到了前10个频率和振型。在对舒适度标准进行全局分析的基础上，提出了实用评价的舒适度指标以及步行激励载荷。同时，采用调谐质量阻尼器（TMD）对采用自锚式悬挂复合箱梁建造的大跨度人行桥进行减振，以确定其适用性。此外，TMD 布局使用 GA 进行了优化。结果表明,所提方法可为大跨度复合式人行桥的动力设计提供理论依据和参考。