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Assessment of Vertical Dynamic Responses in a Cracked Bridge under a Pedestrian-Induced Load

Authors :
Bin Zhen
Sifan Lu
Lijun Ouyang
Weixin Yuan
Source :
Buildings, Vol 14, Iss 9, p 2997 (2024)
Publication Year :
2024
Publisher :
MDPI AG, 2024.

Abstract

Cracks, common indicators of deterioration in bridge frameworks, frequently stem from wear and rust, leading to increased local flexibility and changes in the structure’s dynamic behavior. This study examines how these cracks affect the dynamics of footbridges when subjected to loads generated by walking individuals. The pedestrian is modeled as a linear oscillator, while the cracked bridge is represented by a simply supported beam following Euler–Bernoulli’s theory. The use of the Dirac delta function allows for the precise representation of the localized stiffness reduction at the crack location, facilitating the calculation of analytical expressions for the beam’s vibration modes. The research suggests that the presence of cracks minimally affects the bridge’s mid-span displacement. However, with a limited depth of cracks, the appearance of cracks notably amplifies the mid-span acceleration amplitude of the bridge, leading to a pronounced concentration of energy at the third natural frequency of the bridge in the acceleration spectrum. As the depth and number of cracks increase, the acceleration amplitude continues to decrease, but the corresponding spectrum remains almost unchanged. The study’s outcomes enhance the comprehension of how cracks affect the performance of bridge structures when subjected to loads from pedestrians, offering insights for the monitoring and evaluation of the condition of cracked footbridges.

Details

Language :
English
ISSN :
20755309
Volume :
14
Issue :
9
Database :
Directory of Open Access Journals
Journal :
Buildings
Publication Type :
Academic Journal
Accession number :
edsdoj.1e3fd4dca666489e9781b65e489248fe
Document Type :
article
Full Text :
https://doi.org/10.3390/buildings14092997