A briefing on pedestrian-induced lateral vibration of footbridges

Dallard, Pat; Fizpatrick, Tony; Flint, Anthony; Low, Angus; Ridsdill-Smith, Roger; Willford, Michael

doi:10.1080/12795119.2000.9692692

Cited by 6 publications

(18 citation statements)

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“…However, they concluded that a value of 1 person/m 2 is more probable. During the opening day of the Millennium Bridge in London, the maximum density was 1.3-1.5 people/m 2 [19]. The crowd density on the T-bridge in Japan (also prone to lateral movement) was between 1 and 1.5 people/m 2 [156].…”

Section: Ninety Years Ago Tilden [28] Posed a Question Which Is Stillmentioning

confidence: 99%

“…This is because of the nature of human walking and desire to maintain the body balance on a laterally moving surface. When it occurs, this is known as the synchronisation phenomenon [14] or lock-in effect [19]. As a consequence of the adjusted step when people tend to walk with more spread legs, the motion of the upper torso becomes greater and the pedestrian-induced force becomes larger.…”

Section: Lateral Synchronisationmentioning

confidence: 99%

“…This in turn increases the bridge response and, finally, results in structural dynamic instability [157]. In such circumstances, only reducing the number of people on the footbridge or disrupting/stopping their movement can solve the problem [19], [158], [159], [160] and [161]. It is interesting, however, that in a laboratory experiment [162] with a single pedestrian walking across a laterally moving platform, not every pedestrian walked in a way to boost the lateral vibrations.…”

Section: Lateral Synchronisationmentioning

confidence: 99%

“…Although there have been many reported cases of lively footbridges in the past [14], [15], [16], [17] and [18], this problem attracted considerably greater public and professional attention after the infamous swaying of the new and attractive Millennium Bridge in London during its opening day on 10 June 2000 [19]. The Millennium Bridge problem attracted more than 1000 press articles and over 150 broadcasts in the media around the world.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Ninety Years Ago Tilden [28] Posed a Question Which Is Stillmentioning

confidence: 99%

Section: Lateral Synchronisationmentioning

confidence: 99%

Section: Lateral Synchronisationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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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“…Several experimental measurements allowed this phenomenon to be better understood [1,2]. The crowd walking on a footbridge imposes to the structure a dynamic lateral excitation at a frequency close to 1 Hz.…”

Section: Introductionmentioning

confidence: 99%

Lateral Vibration of Footbridges under Crowd-Loading: Continuous Crowd Modeling Approach

Bodgi¹,

Erlicher²,

Argoul³

2007

Damage Assessment of Structures VII

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Abstract. In this paper, a simple 1D crowd model is proposed, which aim is to properly describe the crowd-flow phenomena occurring when pedestrians walk on a flexible footbridge. The crowd is assumed to behave like a continuous compressible fluid and the pedestrian flow is modeled in a 1-D framework using the (total) mass (of pedestrians) conservation equation. This crowd model is then coupled with a simple model for the dynamical behavior of the footbridge and an optimized modeling of synchronization effects is performed. Numerical simulations are presented to show some preliminary results.

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Lateral crowd‐structure interaction model to analyse the change of the modal properties of footbridges

Jiménez‐Alonso

Sáez

Caetano

et al. 2019

Struct Control Health Monit

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In this paper, a biomechanical crowd-structure interaction model is proposed and calibrated in order to take into account the change of the modal properties of footbridges in lateral direction induced by the pedestrian walking action.The model involves two submodels, namely, (a) the pedestrian-structure interaction and (b) the crowd submodels. In the first submodel, a single degree of freedom system, which simulates the behaviour of each pedestrian, is projected on the vibration modes of the structure. Herein, the parameters of the first submodel are estimated experimentally from the results of several pedestrian tests conducted on a real footbridge. For the second submodel, the crowd behaviour is modelled via a multiagent method. The performance of the overall model has been assessed successfully via the correlation between the change of the first experimental lateral natural frequency of another footbridge during a pedestrian test and the numerical predictions provided by the proposed model. Therefore, this model becomes a valuable tool to analyse numerically the change of the modal parameters of footbridges due to the pedestrianstructure interaction.KEYWORDS change of natural frequencies, crowd dynamics, footbridge, lateral lock-in phenomenon, pedestrianstructure interaction, simplified biomechanical model | INTRODUCTIONAfter the vibratory problems occurred during the opening ceremony of the Millennium footbridge (London, UK), 1 the analysis of the behaviour of footbridges, due to the lateral pedestrian induced vibrations, has become an essential part of their structural design. 2 During the last two decades, many models have been proposed in the literature to simulate the excitation generated by the pedestrian-induced lateral vibrations. These models may be classified into one of the following categories: (a) direct resonance, (b) internal resonance, and (c) dynamic interaction between the pedestrians and the footbridge. 3 Herein, the proposed model can be ascribed to this third category, where the excitation mechanism is originated by the coexistence of an interaction between both pedestrians and the movement of the bridge and among pedestrians themselves.The first attempt to simulate the pedestrian-structure interaction was based on the assumption that a walking pedestrian may be modelled by a pendulum walking model, where a lumped mass situated at the pedestrian's centre of gravity is linked to the structure by a rigid massless element. In 1992, this idea was used by Abe and Fujino 4 to propose a non-linear model for the lateral pedestrian force in terms of the inertial force of the pedestrian and the

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A briefing on pedestrian-induced lateral vibration of footbridges

Cited by 6 publications

References 0 publications

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

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

Lateral Vibration of Footbridges under Crowd-Loading: Continuous Crowd Modeling Approach

Lateral crowd‐structure interaction model to analyse the change of the modal properties of footbridges

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