行人密度的增加会引起步行速度、步行力的基频和一阶分量降低,从而导致结构振动响应随人数增长的规律发生改变。针对该问题,本文考虑了不同人群密度下步行速度的变化,引入已有经验关系获得相应步行速度下的步频,进一步结合相关试验结果确定相应的步行力频谱参数,在此基础上导出人员密度影响系数的计算表达式。结果表明:在人群密度不超过0.3人/m2时,结构振动响应按人数平方根倍关系增长;在人群密度超过0.3人/m2后,增长倍数按步行力频率与结构频率比的大小,可划分为非共振区和诱发共振区,在非共振区,增长倍数低于人数的平方根倍,在诱发共振区,步频改变可能诱发共振,从而导致增长倍数高于人数的平方根倍。
Abstract
Increase in pedestrian density can lead to decrease in walking speed, and the first order component and its frequency of pedestrian loads. This can further change the variation law of structural vibration responses with increase in pedestrian number. Aiming at this problem, considering walking speeds varying under different crowd densities, introducing the existing empirical relationship to get the pedestrian’s step frequency under the corresponding walking speed, combining with the related test results to determine the corresponding spectral parameters of pedestrian loads, based on these the formula for the influence coefficient of pedestrian density were derived. The results showed that the structural vibration response increases with increase in the square root of pedestrian number when the crowd density is less than 0.3 persons/m2; after the crowd density is larger than 0.3 persons/m2, according to the ratio of the pedestrian’s step frequency to the structure’s frequency, there are two regions including the non-resonance region and the induced resonance region; in the non-resonance region, the growth multiple of structural vibration response is less than that of the square root of pedestrian number; in the induced resonance region, the change of the pedestrian’s step frequency may induce resonance, thus the growth multiple of structural vibration response is higher than that of the square root of pedestrian number.
关键词
人群 /
密度 /
人人相互作用 /
结构 /
振动
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Key words
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crowd, density, interaction effect among pedestrians, structure, vibration
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参考文献
[1]Matsumoto Y, Nishioka T, Shiojiri H. Dynamic design of footbridges. International Association for Bridge and Structural Engineering Proceedings, 1978: 17-28.
[2]钱晓斌. 行走作用下结构振动的响应谱分析方法及人群作用分析[D]. 杭州:浙江大学,2005.
Qian Xiao-bin. Acceleration response spectrum method of structure under pedestrian excitation and the analysis of crowd excitation [D]. Hangzhou City: Zhejiang University, 2005.
[3]陈隽,李果,楼佳悦,王磊. 跳跃荷载下大跨楼盖的振动加速度响应谱[J]. 同济大学学报(自然科学版),2015, 43(7): 972-979.
Chen-jun, Li-guo, Lou jia-yue, Wang-lei.Acceleration response spectrum for predicting floor vibration subjected to occupants jumping [J]. Journal of Tongji University (natural science), 2015, 43(7): 972-979.
[4]宋志刚,张尧.人-桥动力相互作用下侧向振动的动力放大系数分析[J]. 振动与冲击,2015,34(1): 19-23.
Song Zhi-gang, Zhang-yao. Analysis of the dynamic amplification factor of lateral structural vibration induced by crowd-bridge interaction [J]. Journal of vibration and shock, 2015, 34(1): 19-23.
[5]Sétra, Footbridge, Assessment of Vibrational Behavior of Footbridges under Pedestrian Loading, desroutes et autoroutes, Technical guide, 2006.
[6]Chen Jun, Peng Yi-xin, Ye Ting. On methods for extending a
single footfall trace into a continuous force curve for floor
vibration serviceability analysis[J]. Structural Engineering
and Mechanics, 2013, 46( 2): 179-196.
[7]Bachmann H. Vibration upgrading of gymnasia, dance halls and footbridges[J]. structural Engineering International, 1992(2): 118-124.
[8]Fujion Y, Pacheco B.M. Nakamura S.I. and Wamitchai E Synchronization of human walking observed during lamral vibration of a congested pedestrian bridge [J]. Earthquake Engineering & Structural Dynamics. 1993, 22(9): 741-758.
[9]Nakamura S.I. Held measurements of lateral vibration on a pedestrian suspension bridge [J]. Structural Engineer. 2003, 81(22): 22-26.
[10] Venuti F, Bruno L. Crowd-structure interaction in lively footbridges under synchronous lateral excitation: A literature review [J]. Physics of Life Review, 2009, 6: 176-206.
[11]J.E. Bertram, A Ruina, Muliple walking speed-frequency relations are predicted by constrained optimization [J]. Theor. Biol. 2001, 209: 445-453.
[12]Venuti Fiammetta, Bruno Luca. An interpretative model of the pedestrian fundamental relation [J]. Comptes Rendus Mecanique, 2007, 335(4): 194-200.
[13]Kerr S C. Human induced loading on staircases [D]. University of London, 1998.
[14]Young P. Improved floor vibration prediction methodologies[C]. Arup Vibration Seminar, 2001.
[15]Bachmann H, Ammann W. Vibrations in structures: Induced by man and machines [M]. Iabse, 1987.
[16]陈隽,王浩祺,彭怡欣. 行走激励的傅里叶级数模型及其参数的实验研究[J]. 振动与冲击2014, 33(8): 11-15.
Chen –jun, Wang Hao-qi, Peng Yi-xin. Experimental investigation on Fourier-series model of walking load and its coefficients[J]. Journal of vibration and shock, 2014, 33(8): 11-15.
[17]BSI. Steel, concrete and composite bredges[Z]//part 2: specification for loads, Appendix C: Vibration Serviceability Requirements for Foot and Cycle Track Bridges(BS 5400: part 2: 1978). British Standard Institution, London, 1978.
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