西单过街天桥人致振动分析

发布时间：2018-12-29 15:42

【摘要】：近年来,随着城市化进程的不断加快,越来越多的人涌入城市。为了缓解商业街交通压力,过街人行天桥开始频繁现身各大商业区,成为必不可少的交通辅助工具。但是,由于高峰期人流的不确定性,人行天桥蓬勃发展的背后也隐藏着巨大的安全风险。商业街人行桥由于处在城市繁华区,这样的地理位置,使得它在保障自身功能的基础上,开始向着轻柔、美观的方向发展。而这种特点往往会导致桥梁自身刚度和阻尼大幅降低,同时伴随着固有频率的降低,在“人行桥高峰”阶段容易产生振动,威胁行人的安全。针对这种情况,控制桥上行人数成了有效的解决办法。这就需要找到合适的办法预估安全人数,为管理部门采取限流和安保措施提供技术支持。那么如何尽可能准确的预测出桥上安全人数就成了很有研究价值的课题,本文将尝试解决这个问题。本人通过实地调研,采集到了桥上行人的步频,通过数据处理得出了平均步频,进而确定了人行桥的敏感频率。接着通过有限元软件构建了人行桥的有限元模型,先是进行了模态分析,用模态分析的结果与实测值对比,保证了模型的实用性。基于模态分析的结果确定了该桥研究的必要性。在保证了模型的精确性与实用性之后,选取了国内外应用较为成熟的荷载模型和人致振动研究方法,针对不同的人群密度工况对该模型进行有限元仿真,得出不同密度下的最大加速度,最后依据舒适度评价方法对该人行桥进行了舒适度评价,得出了不同工况时的舒适度情况,进而得到人行桥安全人数的控制范围。
[Abstract]:In recent years, with the acceleration of urbanization, more and more people pour into cities. In order to relieve traffic pressure, pedestrian overpasses frequently appear in various commercial districts and become necessary traffic aids. However, due to the uncertainty of passenger flow during the peak period, there are huge security risks behind the vigorous development of pedestrian overpasses. The pedestrian bridge in commercial street is located in the bustling area of the city, which makes it develop gently and aesthetically on the basis of ensuring its own function. This characteristic often leads to the reduction of the stiffness and damping of the bridge itself, and with the decrease of the natural frequency, it is easy to produce vibration in the peak stage of the footbridge and threaten the safety of pedestrians. In view of this situation, the control bridge uplink has become an effective solution. This requires finding an appropriate way to estimate the number of safe people and provide technical support for management to take current containment and security measures. So how to predict the number of safety on the bridge as accurately as possible has become a valuable research topic, this paper will try to solve this problem. Through the field investigation, I collected the pedestrian's step frequency on the bridge, obtained the average step frequency through the data processing, and then determined the sensitive frequency of the pedestrian bridge. Then the finite element model of the footbridge is constructed by the finite element software. First, the modal analysis is carried out, and the results of the modal analysis are compared with the measured values to ensure the practicability of the model. Based on the results of modal analysis, the necessity of studying the bridge is confirmed. After ensuring the accuracy and practicability of the model, the load model and the human vibration research method, which are used mature at home and abroad, are selected, and the finite element simulation of the model is carried out according to different population density working conditions. The maximum acceleration at different densities is obtained. Finally, the comfort degree of the footbridge is evaluated according to the comfort evaluation method, and the comfort degree of the footbridge under different working conditions is obtained, and the control range of the safety number of the footbridge is obtained.
【学位授予单位】：首都经济贸易大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U441.3

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