Pedestrian bridges structure; assessment of comfort and impact of human-induced vibration

Gaawan, Sameh; El-Robaa, Ahmed

doi:10.3233/brs-190148

Cited by 2 publications

(2 citation statements)

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“…Consequently, these footbridges are more prone to dynamic vibrations induced by pedestrian excitation that can compromise the comfort serviceability conditions (Bachmann, 1992;Blekherman, 2005;Chen and Hua, 2009). Note that footbridges may have suffered from resonance problems because of the equivalence of the human-induced frequency and the structural natural frequency, which severely influences the pedestrian comfort and structural safety (Gaawan and El-Robaa, 2019). Therefore, the assessment of pedestrian comfort and control of humaninduced vibration of footbridge is a topical issue in the vibration serviceability analysis.…”

Section: Introductionmentioning

confidence: 99%

“…Generally, the fundamental frequency of the vertical loading corresponds to the pedestrian step frequency, yet the fundamental frequency of the lateral loading is half to the step frequency. The existing research results indicated that footbridges of vertical vibration fundamental frequency and lateral vibration fundamental frequency were respectively less than 5 and 1.4 Hz (Chen and Hua, 2009;Fujino et al, 1993;Gaawan and El-Robaa, 2019), on the other hand, the vertical acceleration that pedestrians can tolerate was about five times to the lateral acceleration (Dallard, 2005;Dziuba, 2012). Therefore, these footbridges are prone to exert the large lateral vibration under periodic loading, and not susceptible to the synchronized resonance under the bridge-pedestrian interaction.…”

Section: Introductionmentioning

confidence: 99%

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Study on human-induced vibration of a cable-stayed bridge without backstays located in abrupt valley

Sun

2021

Advances in Structural Engineering

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This research aims to assess the pedestrian comfort and to control human-induced vibration of an arch tower cable-stayed bridge without backstays located in canyon. Dynamic simulations of human-induced vibration were carried out with a mode-by-mode approach, and the results indicated that a total of seven lateral and vertical modes of the bridge may suffer from excessive vibrations at the design crowd density. Based on the periodic walking force, the structure response under pedestrian loads was evaluated performing dynamic analyses with two Finite Element models of the footbridge. A single tuned mass damper (STMD) control system was developed for control of human-induced vibration, which consisted of four tuned mass dampers mounted on the mid-span of bridge to enhance damping ratios of lively modes. The results indicate that the maximum acceleration for the first-order lateral and second-order vertical vibration at the design crowd density exceed the associated threshold values referring to the comfort level 1 (CL1) Criteria. The critical pedestrian number of lateral dynamic instability estimated by the Dallard’s empirical formula is much smaller than the dynamic design pedestrian number; and the Dallard’s empirical formula is applicable to estimate the critical pedestrian number of lateral dynamic instability for this bridge by comparing with Pedroe Inês footbridge. The damping ratios for both the vertical and lateral modes increase appreciably after installing the tuned mass dampers and no evidence of large-amplitude vibrations has been observed, leading to the realization of satisfactory comfort levels, which can provide reference for vibration reduction design of this kind of bridge.

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Section: Introductionmentioning

confidence: 99%