A footbridge known to be lively under vertical pedestrian excitation was tested and the lowest modes of vibration were identified. It was established that the first vertical mode had the natural frequency of 2.05 Hz and a very low damping ratio of only 0.28 percent. These were the main factors which influenced most of 300 randomly interviewed pedestrians to rate the footbridge as lively. A detailed finite element model was developed and formally updated using a sensitivity based model updating approach to match the measured natural frequencies. By monitoring pedestrian traffic, pedestrian arrival time distribution and frequency distribution of their steps were identified. Using these data and modal properties of the updated finite element model, the vibration response of the bridge to everyday pedestrian traffic was simulated using a stochastic approach (Monte Carlo simulations) and compared with the measured acceleration.
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机译：已经测试了一种已知在垂直行人激励下热闹的行人桥，并鉴定了最低振动模式。建立了第一垂直模式的自然频率为2.05 Hz，阻尼比的极低阻尼比仅为0.28％。这些是影响大多数300名随机采访的行人的主要因素，以便热闹地利用行人桥。开发了一种详细的有限元模型，并使用基于灵敏度的模型更新方法进行了开发并正式更新，以匹配测量的自然频率。通过监测行人交通，识别步行到达时间分布和频率分布的步骤。使用这些数据和更新的有限元模型的模态属性，使用随机方法（Monte Carlo Simulations）进行模拟桥梁到日常行程流量的振动响应，并与测量的加速相比。
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