Biomechanically inspired modelling of pedestrian-induced forces on laterally oscillating structures
Biomechanically inspired modelling of pedestrian-induced forces on laterally oscillating structures
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DOI：
10.1016/j.jsv.2012.03.023
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发表时间：
2012-07-30
影响因子：
4.7
通讯作者：
Burn, J. F.
中科院分区：
文献类型：
--
作者：
Bocian, M.;Macdonald, J. H. G.;Burn, J. F.
尽管工程师和科学家们对此很感兴趣，但步行行人和活跃桥梁之间的双向互动仍然没有得到很好的理解。在试图弥合这一差距的生物力学启发模型的人的横向桥梁运动的反应，并探讨。简单的倒立摆模型捕捉行人横向平衡的关键特征和结构上的合力。力包括自激分量，其可以有效地建模为对结构的频率依赖性附加阻尼和质量。数值模拟的结果是在合理的协议与最近的实验测量的人走在横向振荡的跑步机，并在非常好的协议与测量全尺寸的桥梁。与许多其他横向行人荷载模型相比，不涉及与桥梁运动的同步。模型的参数研究，揭示了行人放慢速度，人群变得更加密集，他们由此产生的较低的步速产生较大的自激力。对于典型的行人参数，对于任何高于0.43 Hz的横向桥梁振动频率，产生负阻尼的可能性会增加，这取决于步行频率。结合桥梁结构系统的稳定性边界的结构阻尼比和桥梁的质量比，揭示阻尼需求和桥梁和行人的频率之间的复杂关系，由于附加的质量效应。最后，它表明，该模型可以同时产生多个结构模式的自激力，和一个现实的充分模拟大量的行人，随机行走和互动的桥梁，产生结构行为与现场观察非常吻合。(C)2012爱思唯尔有限公司保留所有权利。
Despite considerable interest among engineers and scientists, bi-directional interaction between walking pedestrians and lively bridges has still not been well understood. In an attempt to bridge this gap a biomechanically inspired model of the human response to lateral bridge motion is presented and explored. The simple inverted pendulum model captures the key features of pedestrian lateral balance and the resulting forces on the structure. The forces include self-excited components that can be effectively modelled as frequency-dependent added damping and mass to the structure. The results of numerical simulations are in reasonable agreement with recent experimental measurements of humans walking on a laterally oscillating treadmill, and in very good agreement with measurements on full-scale bridges. In contrast to many other models of lateral pedestrian loading, synchronisation with the bridge motion is not involved. A parametric study of the model is conducted, revealing that as pedestrians slow down as a crowd becomes more dense, their resulting lower pacing rates generate larger self-excited forces. For typical pedestrian parameters, the potential to generate negative damping arises for any lateral bridge vibration frequency above 0.43 Hz, depending on the walking frequency. Stability boundaries of the combined pedestrian-structure system are presented in terms of the structural damping ratio and pedestrian-to-bridge mass ratio, revealing complex relations between damping demand and bridge and pedestrian frequencies, due to the added mass effect. Finally it is demonstrated that the model can produce simultaneous self-excited forces on multiple structural modes, and a realistic full simulation of a large number of pedestrians, walking randomly and interacting with a bridge, produces structural behaviour in very good agreement with site observations. (C) 2012 Elsevier Ltd. All rights reserved.