Measuring and Modeling Dynamic Loads Imposed by Moving Crowds

Ebrahimpour, Arya; Hamam, Abdelwahab; Sack, Ronald L.; Patten, William

doi:10.1061/(asce)0733-9445(1996)122:12(1468)

Cited by 93 publications

(40 citation statements)

References 8 publications

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“…Some studies on coherency, which concern relative phase angles among pedestrians, were done by Ebrahimpour et al ( [25], [26]). Piccardo & Tubino [9], dealing with unrestricted pedestrian traffic, assumed as a coherence function the Dirac delta function in order to model perfect uncorrelation.…”

Section: A Phisically-based Coherence Functionmentioning

confidence: 99%

Equivalent Spectral Model for Pedestrian-Induced Forces on Footbridges: A Generalized Formulation

Ferrarotti¹,

Tubino²

2015

Proceedings of the 5th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

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Section: A Phisically-based Coherence Functionmentioning

confidence: 99%

Equivalent Spectral Model for Pedestrian-Induced Forces on Footbridges: A Generalized Formulation

Ferrarotti¹,

Tubino²

2015

Proceedings of the 5th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

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“…Serviceability in modern structures constructed by high strength and lightweight materials is the most important issue and should be considered in addition to the strength/safety criteria [6,12]. In case of evaluation of vibration serviceability, generally codes and standards present two approaches.…”

Section: Introductionmentioning

confidence: 99%

Dynamic response of low frequency Profiled Steel Sheet Dry Board with Concrete infill (PSSDBC) floor system under human walking load

Gandomkar

Badaruzzaman

Osman

2012

Lat. Am. j. solids struct.

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This paper investigates the dynamic response of a composite structural system known as Profiled Steel Sheet Dry Board with Concrete infill (PSSDBC) to evaluate its vibration serviceability under human walking load. For this point, thirteen (13) PSSDBC panels in the category of Low Frequency Floor (LFF) were developed using Finite Element Method (FEM). The natural frequencies and mode shapes of the studied panels were determined based on the developed finite element models. For more realistic evaluation on dynamic response of the panels, dynamic load models representing human walking load were considered based on their Fundamental Natural Frequency (FNF), and also time and space descriptions. The peak accelerations of the panels were determined and compared to the limiting value proposed by the standard code ISO 2631-2. Effects of changing thickness of the Profiled Steel Sheet (PSS), Dry Board (DB), screw spacing, grade of concrete, damping ratio, type of support, and floor span on the dynamic responses of the PSSDBC panels were assessed. Results demonstrated that although some factors reduced dynamic response of the PSSDBC system under human walking load, low frequency PSSDBC floor system could reach high vibration levels resulting in lack of comfortableness for users. Keywords structural composite floor system, profiled steel sheet dry board, vibration serviceability, human walking load, dynamic response, human comfort.

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“…Measurements of individual step forces were followed by the more advanced and informative measurements of continuous walking time histories comprising several steps. For this purpose Blanchard et al [34] used a gait machine described by Skorecki [41], Rainer et al [42] used a floor strip, whereas Ebrahimpour et al [43] and [44] used a platform instrumented with several force plates. The measured time histories were obviously near periodic with the (average) period equal to reciprocal value of the (average) step frequency.…”

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confidence: 99%

“…An identical procedure was applied on walking loads by Ebrahimpour et al [44]. A vertical dynamic load by a group of pedestrians was investigated.…”

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confidence: 99%

Vibration serviceability of footbridges under human-induced excitation: a literature review

Živanović

Pavić

Reynolds

2005

Journal of Sound and Vibration

521

315

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Increasing strength of new structural materials and longer spans of new footbridges, accompanied with aesthetic requirements for greater slenderness, are resulting in more lively footbridge structures. In the past few years this issue attracted great public attention. The excessive lateral sway motion caused by crowd walking across the infamous Millennium Bridge in London is the prime example of the vibration serviceability problem of footbridges. In principle, consideration of footbridge vibration serviceability requires a characterisation of the vibration source, path and receiver. This paper is the most comprehensive review published to date of about 200 references which deal with these three key issues.The literature survey identified humans as the most important source of vibration for footbridges. However, modelling of the crowd-induced dynamic force is not clearly defined yet, despite some serious attempts to tackle this issue in the last few years.The vibration path is the mass, damping and stiffness of the footbridge. Of these, damping is the most uncertain but extremely important parameter as the resonant behaviour tends to govern vibration serviceability of footbridges.A typical receiver of footbridge vibrations is a pedestrian who is quite often the source of vibrations as well. Many scales for rating the human perception of vibrations have been found in the published literature. However, few are applicable to footbridges because a receiver is not stationary but is actually moving across the vibrating structure.During footbridge vibration, especially under crowd load, it seems that some form of humanstructure interaction occurs. The problem of influence of walking people on footbridge vibration properties, such as the natural frequency and damping is not well understood, let alone quantified.Finally, there is not a single national or international design guidance which covers all aspects of the problem comprehensively and some form of their combination with other published information is prudent when designing major footbridge structures. The overdue update of the current codes to reflect the recent research achievements is a great challenge for the next 5-10 years. Abbreviations:ASD-auto spectral density; DLF-dynamic load factor; DOF-degree of freedom; FE-finite element;FRF-frequency response function; MDOF-multiple-degree-of-freedom;MTMD-multiple tuned mass damper; RMS-root-mean-square;SDOF-single-degree-of-freedom; TLD-tuned liquid damper; TMD-tuned mass damperThis paper has been published under the following reference:Živanović, S., Vibration serviceability of footbridges under human-induced excitation: a literature review.

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Measuring and Modeling Dynamic Loads Imposed by Moving Crowds

Cited by 93 publications

References 8 publications

Equivalent Spectral Model for Pedestrian-Induced Forces on Footbridges: A Generalized Formulation

Equivalent Spectral Model for Pedestrian-Induced Forces on Footbridges: A Generalized Formulation

Dynamic response of low frequency Profiled Steel Sheet Dry Board with Concrete infill (PSSDBC) floor system under human walking load

Vibration serviceability of footbridges under human-induced excitation: a literature review

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