Abstract

Despite extensive research in the field of human-induced vibration in the last twenty years, there is still lack of reliable load and response models to assess vibration serviceability of footbridges under human-induced excitation, especially with reference to crowded conditions. This paper aims to provide a reliable characterization of pedestrian-induced loading on footbridges in restricted traffic condition, and to compare the reliability of current guidelines and advanced spectral models in the serviceability assessment of footbridges with respect to vertical vibrations. Numerical simulations of restricted pedestrian traffic are carried out through an agent-based model, considering variable pedestrian densities and deck widths. The probability distribution of the step frequency and the power spectral density function of the modal force are obtained numerically. Based on the numerical results, a Modified Generalized Equivalent Spectral Model is proposed. Finally, two numerical examples are analyzed to assess the reliability of current guidelines and of the Modified Generalized Equivalent Spectral Model in the estimate of the maximum footbridge acceleration.

摘要

尽管近二十年来在人为振动领域进行了广泛的研究，但仍然缺乏可靠的载荷和响应模型来评估人为激励下人行桥的振动适用性，尤其是在拥挤条件下。本文旨在提供交通受限条件下人行桥上行人引起的载荷的可靠表征，并比较当前指南和先进频谱模型在人行桥垂直振动适用性评估中的可靠性。受限行人交通的数值模拟是通过基于代理的模型进行的，考虑到可变的行人密度和甲板宽度。数值计算得到阶跃频率的概率分布和模态力的功率谱密度函数。基于数值结果，提出了一种改进的广义等效谱模型。最后，分析了两个数值例子，以评估当前指南和修正广义等效谱模型在估计最大人行桥加速度方面的可靠性。