双向人群流疏导的人行桥减振控制研究

Study on Vibration Reduction Control of Pedestrian Bridge with Bidirectional Crowd Flow Diversion

提出了通过布置障碍物进行双向人群流的疏导来控制结构振动的方法.利用考虑行人自停和减速避让的改进后的社会力模型对双向人群运动进行仿真模拟,将每个行人视为MSD模型建立人-结构相互作用的耦合系统以及振动控制方程,计算结构的振动响应.以实验室人行桥为算例,研究布置障碍物对行人步行特性的改变和对结构振动的影响,并从能量的角度解释了减振机理.算例结果表明,当双向人群密度超过0.6人/m^(2)时引起的结构振动会导致行人产生不适感,在人行桥上布置4个障碍物后,双向分别有1人和2人的工况下减振率达到12.4%和13.1%,且输入结构的能量大幅降低,结构输出的质量动能、粘滞阻尼能和弹性应变能降低率分别达到38.46%、67.48%和50.68%.研究内容可为大跨人行桥的减振方法提供思路.

This paper proposes a method to control structural vibrations by arranging obstacles to divert the bidirectional crowd flow.A modified social force model that takes into account pedestrian self-stopping and deceleration avoidance is used to simulate the bidirectional crowd movement.Each pedestrian is regarded as an MSD model to establish a coupled system of human-structure interaction and vibration control equations,and calculate the vibration response of the structure.A laboratory footbridge is used as an example to investigate the effect of obstacle placement on pedestrian walking characteristics and structural vibration,and to explain the damping mechanism from an energy perspective.The results show that the structural vibration caused by the bidirectional crowd density exceeding 0.6 pedestrians per square meter leads to pedestrians’discomfort,and after arranging four obstacles on the pedestrian bridge,the vibration reduction rate reaches 12.4% and 13.1% for the two directions with one pedestrian and two pedestrians,respectively,and the energy input to the structure is significantly reduced.The reduction rates of mass kinetic energy,viscous damping energy,and elastic strain energy output of the structure reached 38.46%,67.48%,and 50.68%,respectively.The research can provide ideas for vibration reduction methods for large-span pedestrian bridges.