Probabilistic Approaches to the Ergonomical Serviceability of Pedestrian-Bridges

Kajikawa, Yasuo; Kobori, Tameo

doi:10.2208/jscej1969.1977.266_51

Cited by 8 publications

(5 citation statements)

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“…However, it is not quite clear what this statement precisely means and how the results are processed. The same authors investigated the possibility that a footbridge will be unserviceable under a number of pedestrians [136]. Using probability theory and assuming a Poisson distribution of pedestrian arrivals as well as a normal distribution of human response, they found the probability that serviceability of a footbridge will not be satisfied, in terms of a percentage of pedestrians who will feel an unacceptable level of vibrations.…”

Section: Perception Of Vertical Vibrations On Bridgesmentioning

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

516

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: Perception Of Vertical Vibrations On Bridgesmentioning

confidence: 99%

“…18. Unfortunately, none of these two articles [135] and [136] contains a list of pertinent references which could help to understand better the approach proposed. It should be noted that velocity is adopted as the parameter for evaluation of footbridge serviceability in Japan [55].…”

Section: Perception Of Vertical Vibrations On Bridgesmentioning

confidence: 99%

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

Živanović

Pavić

Reynolds

2005

Journal of Sound and Vibration

516

315

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“…Different codes and studies provide various methods for the determination of R. In Japan, Kajikawa and Kobori (1977) performed large-scale shaking table experiments to assess people's feelings and suggested that the effective value is an appropriate index for evaluating the vibration comfort of bridges, with a mean threshold value of 1.7 cm/s, peak value of 2.4 cm/s, and variance of 0.6 cm/s. The codes used in other countries have different limits on the peak acceleration values, as shown in Figure 1 and Table 1.…”

Section: Probability-based Vibration Comfort Assessmentmentioning

confidence: 99%

“…Ž ivanovic´and Pavia (2009) highlighted the pedestrian bridge vibration amplitude limitation by considering the response of pedestrians using probability theory, thereby determining the relationship between the vibration amplitude of a pedestrian bridge and the vibration comfort of pedestrian subjects. Kajikawa and Kobori (1977) studied the pedestrian bridge vibration comfort index using probability theory and proposed a method based on the effective structure velocity values to check the vibration comfort. Ž ivanovic´and Pavia (2011) analyzed the probability distribution characteristics of pedestrian bridge vibration responses to a step load using experimental and numerical methods.…”

Section: Introductionmentioning

confidence: 99%

Comfort assessment for a pedestrian passageway suspended under a girder bridge with random traffic flows

Chen

Xie

et al. 2016

Advances in Structural Engineering

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In recent years, a new type of pedestrian passageway, which is suspended under the main girder bridge, has emerged. Vibration in this type of structure is mainly due to the vehicle traffic loading on the main bridge. However, the current codes are not appropriate for vibration comfort assessments for these pedestrian passageways. In this study, a novel method was proposed for probability-based vibration comfort assessment, which considers the randomness of traffic flows. Using an in-service suspended pedestrian bridge as an example, it was considered to the factors that influence the vibration comfort using field measured traffic loading. The results showed that the peak acceleration response of the pedestrian bridge under a random traffic flow followed a normal distribution and there were some deviations in the vibration comfort assessment results when different codes are used. Factors such as the vehicle type ratio, roughness of the pavement, and vehicle speed had significant effects on the acceleration response of the structure.

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“…Alternative descriptions are also applied. In 1997, Kajikawa and Kobori investigated the possibility that a footbridge become unserviceable under a number of pedestrians [4]. Assuming a Poisson distribution of pedestrian arrivals and normal distribution of human response they described the footbridge serviceability in terms of a percentage of pedestrian who felt an unacceptable level of vibrations.…”

Section: The Footbridges Serviceability Descriptionsmentioning

confidence: 99%

A probabilistic description of footbridges vibration serviceability

Winkelmann

Górski

2009

Proc Appl Math and Mech

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Vibration serviceability of pedestrian bridges is considered. Imperfections in the human walking force are described as changes in walking factors. Probability distributions of walking frequencies, step length, and amplitude of walking force are taken into account. The imperfections can influence the level of footbridge vibration response. The Monte Carlo method is applied. The generated realizations of the loads formulate a set of initial data for numerical calculations. The probability distribution of maximal vertical acceleration is obtained. The results are presented as a probability that the required level of vibration will not be exceeded. A reliability describing the footbridges serviceability is also estimated. The probabilistic based approach can be used for future optimalizations of footbridge design codes due to the dynamic force loads.

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Probabilistic Approaches to the Ergonomical Serviceability of Pedestrian-Bridges

Cited by 8 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

Comfort assessment for a pedestrian passageway suspended under a girder bridge with random traffic flows

A probabilistic description of footbridges vibration serviceability

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