Numerical Investigation On The Influence Of Bidirectional Restraint Performance Of Shear Keys On Coastal Girder Bridges Under Extreme Wave Loads

Abstract

Coastal girder bridges are highly vulnerable to beam unseating failures under extreme wave actions. Bidirectional shear keys with horizontal and vertical restraints can effectively improve the disaster resilience of bridge superstructures. However, the effects of key design parameters on their restraining performance remain unclear. In this study, numerical simulations are conducted to investigate the effects of three parameters—prestressing level of the shear key, initial gap between the shear key and the girder, and wave height—on the dynamic responses of a bridge subjected to simulated wave loads. The restraining performance is significantly affected by the prestressing level. Without prestress, the weakest restraint is obtained, and evident residual deformation is observed. When the prestress reaches 70% cr, of the steel yield strength, the lateral restraint capacity is enhanced, and residual deformation is effectively suppressed. Increasing the prestress to 90% cr, provides only limited improvement. The initial gap markedly influences impact-energy regulation; a zero gap induces excessive initial impact forces, while an overly large gap (5 mm) allows excessive kinetic energy accumulation prior to contact, which is unfavorable for structural safety; in contrast, a 2 mm gap achieves a balanced performance between impact mitigation and effective restraint. Moreover, the impact mechanisms vary significantly with wave height. As the wave height increases, the wave regime changes from a non-breaking solitary wave to a breaking bore. The trapped air beneath the bridge deck is then compressed more intensely. Structural responses reach their peak near a critical wave height of approximately 1. 32 m and subsequently level off or slightly decrease due to enhanced energy dissipation associated with wave breaking.

Department(s)

Civil, Architectural and Environmental Engineering

Keywords and Phrases

bidirectional restraint; coastal girder bridge; extreme wave loads; finite element analysis; fluid-structure interaction; shear key

International Standard Serial Number (ISSN)

1000-3835

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2026 Tongfang CNKI (Beijing) Technology C., Ltd, All rights reserved.

Publication Date

15 Sep 2026

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