Human Jumping and Bobbing Forces on Flexible Structures: Effect of Structural Properties
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Volume 134, Issue 8
Abstract
The behavior of humans jumping and bobbing on flexible structures has become a matter of some concern for both structural integrity and human tolerance. The issue is of great importance for a number of structure types including stadia terraces. A unique test rig has been developed for exploring the forces, accelerations, and displacements that occur when a human subject jumps or bobs on a flexible structure where motion can be perceived. In tests reported earlier, it was found that the subject is able to generate near resonant structural response but it is extremely difficult, if not impossible, to jump or bob at or very near to the natural frequency of the structure when its vertical motion is significant. Also, under such near-resonant conditions, the force developed by the subject was found to drop significantly. In this paper, the effect of altering the subject-to-structure mass ratio and the damping ratio of the structure on these phenomena is presented. As would be expected, it is shown that as the structure becomes more massive and more highly damped it moves less for nominally the same excitation. In this situation, it becomes easier to jump and bob near to resonance and the degree of force dropout reduces, although it is still significant for even the most massive and highly damped case considered. A method for including these effects of human-structure interaction in a load model for dynamic response calculations is then proposed.
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Acknowledgments
The writers gratefully acknowledge the support of the Engineering and Physical Sciences Research Council (EPSRC) and Arup who have funded the two projects under which this work was carried out. The writers also appreciate helpful discussions with members of the IStructE Joint Working Group in the United Kingdom dealing with dynamic crowd loading on seating decks.
References
Bachmann, H., and Ammann, W. J. (1987). Vibration in structures: Induced by man and machines, IABSE, Zurich, Switzerland.
Bachmann, H., et al. (1995). Vibration problems in structures: Practical guidelines, Birkhäuser, Basel, Switzerland.
British Standards Institution (BSI). (1987). BS6841 Measurement and evaluation of human exposure to whole-body mechanical vibration and repeated shock, London.
British Standards Institution (BSI). (1992). BS6472 Evaluation of human exposure to vibration in buildings ( to ), London.
British Standards Institution (BSI). (1996). BS6399 Loading for buildings—Part 1: Code of practice for dead and imposed loads, London.
Building Research Establishment (BRE). (2004). Digest 426: The response of structures to dynamic crowd loads, BRE Bookshop, Watford, U.K.
Culley, P., and Pascoe, J. (2005). Stadium engineering, Thomas Telford, London.
Den Hartog, J. P. (1956). Mechanical vibrations, McGraw-Hill, New York.
Dougill, J. W. (2005). “Recommendations for design of grandstands subject to dynamic crowd excitation.” Proc., 6th European Conf. on Structural Dynamics (EURODYN 2005), European Association for Structural Dynamics (EASD), Munich, Germany, 491–496.
Dougill, J. W., and Wright, J. R. (2005). “A bouncing ball model for periodic human jumping.” Proc., 23rd Int. Modal Analysis Conf. (IMACXXIII), Society for Experimental Mechanics (SEM), Bethel, Conn.
Dougill, J. W., Wright, J. R., Parkhouse, G., and Harrison, R. E. (2006). “Human structure interaction during human bobbing.” Struct. Eng., 84(22), 32–39.
Duarte, E., and Ji, T. (2005). “Bouncing loads induced by an individual.” Proc., 6th European Conf. on Structural Dynamics (EURODYN 2005), European Association for Structural Dynamics (EASD), Munich, Germany, 497–503.
Ellis, B. R., and Littler, J. D. (2004). “Response of cantilever grandstands to crowd loads. Part 1: Serviceability evaluation.” Proc. Inst. Civ. Eng., Struct. Build., 157(SB4), 235–241.
Ginty, D., Derwent, J. M., and Ji, T. (2001). “The frequency ranges of dance-type loads.” Struct. Eng., 79(6), 27–31.
Harrison, R. E., Wright, J. R., and Dougill, J. W. (2006). “Video monitoring of human-structure interaction for bouncing on a flexible structure.” Proc., 24th Int. Modal Analysis Conf. (IMACXXIV), Society for Experimental Mechanics (SEM), Bethel, Conn.
Her Majesty’s Stationary Office (HMSO). (1999). Guide to safety at sports grounds, London.
Institution of Structural Engineers (IStructE). (2001). Dynamic performance requirements for permanent grandstands subject to crowd action: Interim guidance for assessment and design, London.
International Standards Organization (ISO). (1997). ISO 2631-1 Mechanical vibration and shock—Evaluation of human exposure to whole body vibration—Part 1: General requirements, Geneva.
Matsumoto, Y., and Griffin, M. J. (2003). “Mathematical models for the apparent masses of standing subjects exposed to vertical whole-body vibration.” J. Sound Vib., 260(3), 431–451.
National Research Council Canada (NRC). (1995). Users’ guide National Building Code of Canada (NBC): Commentary A—Serviceability criteria for deflections and vibrations, Ottawa.
Parkhouse, J. G., and Ewins, D. J. (2004). “Vertical dynamic loading produced by people moving to a beat.” Proc., Int. Conf. on Noise and Vibration Engineering (ISMA2004), Katholieke Universiteit Leuven, Leuven, Belgium, 821–835.
Reid, W. M., Dickie, J. F., and Wright, J. R. (1997). “Stadium structures: Are they excited?” Struct. Eng., 75(22), 383–388.
Sachse, R., Pavic, A., and Reynolds, P. (2002). “The influence of a group of humans on modal properties of a structure.” Proc., 5th European Conf. on Structural Dynamics (EURODYN 2002), European Association for Structural Dynamics (EASD), Munich, Germany, 1241–1246.
Sim, J., Blakeborough, A., and Williams, M. S. (2005). “Dynamic loads due to rhythmic human jumping and bobbing.” Proc., 6th European Conf. on Structural Dynamics (EURODYN 2005), European Association for Structural Dynamics (EASD), Munich, Germany, 467–472.
Standing Committee on Structural Safety (SCOSS). (2001). “Structural safety 2000-01: Thirteenth report of SCOSS Rep.” IStructE, London.
Tomlinson, G. R. (1987). “A simple theoretical and experimental study of the force characteristics from electrodynamic exciters on linear and nonlinear systems.” Proc., Int. Modal Analysis Conf. (IMACV), Society for Experimental Mechanics (SEM), Bethel, Conn.
Wei, L., and Griffin, M. J. (1998). “Mathematical models for the apparent mass of the seated human body exposed to vertical vibration.” J. Sound Vib., 212(5), 855–874.
Willford, M. (2001). “An investigation into crowd-induced vertical dynamic loads using available measurements.” Struct. Eng., 79(12), 21–25.
Yao, S., Wright, J. R., Pavic, A., and Reynolds, P. (2002). “Forces generated when bouncing or jumping on a flexible structure.” Proc., Int. Conf. on Noise and Vibration Engineering (ISMA2002), Katholieke Universiteit Leuven, Leuven, Belgium, 563–572.
Yao, S., Wright, J. R., Pavic, A., and Reynolds, P. (2004). “Experimental study of human-induced dynamic forces due to bouncing on a perceptibly moving structure.” Can. J. Civ. Eng., 31(6), 1109–1118.
Yao, S., Wright, J. R., Pavic, A., and Reynolds, P. (2006). “Experimental study of human-structure interaction for jumping on a perceptibly moving structure.” J. Sound Vib., 296(1-2), 150–165.
Yao, S., Wright, J. R., Yu, C. H., Pavic, A., and Reynolds, P. (2005). “Human-induced swaying forces on flexible structures.” Proc. Inst. Civ. Eng., Struct. Build., 158(2), 109–117.
Information & Authors
Information
Published In
Journal of Engineering Mechanics
Volume 134 • Issue 8 • August 2008
Pages: 663 - 675
Copyright
© 2008 ASCE.
History
Received: Aug 17, 2006
Accepted: Nov 28, 2007
Published online: Aug 1, 2008
Published in print: Aug 2008
Notes
Note. Associate Editor: Henri P. Gavin
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