PSI - Issue 84

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ScienceDirect

Procedia Structural Integrity 84 (2026) 272–279

© 2026 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the Conference Keywords: hooked and unhooked collars; scour reduction; circular piers; round-nosed rectangular piers. Abstract The study presents the results of laboratory-scale experiments aimed at evaluating the effectiveness of protective collars in reducing local scour at the base of bridge piers. The investigation encompassed both circular and round-nosed rectangular pier geometries, with supplementary tests conducted on hooked collar configurations applied to circular piers. Experimental findings indicate that the application of collars substantially retards the temporal development of scour and reduces its overall depth. The most significant scour reduction was achieved when collars were embedded below the initial bed level but well above the maximum equilibrium scour depth observed in the absence of any countermeasures. The incorporation of hooked collars yielded only marginal improvements in performance compared to conventional (i.e., simple) collar designs. 1. Introduction Erosion at the base of bridge piers is recognized as one of the main causes of the collapse of the structures following the occurrence of river floods (Melville and Coleman, 2000; Lamb et al., 2017; Johnson and Dock, 1996; Lagasse et al., 1995). Evaluation of the maximum local scour, both in clear water and live bed conditions, has been a topic of III Fabre Conference: Existing Bridges, Viaducts, and Tunnels: Research, Innovation, and Applications Laboratory investigation of local scour at collared piers in clear water conditions. Maria Giovanna Tanda a, *, Paolo Mignosa a , Nazarena Bruno a , Elena Carcano b a Department of Engineering and Architecture, University of Parma, Parco Area delle Scienza 181/A, Parma 43124, Italy b Department of Engineering, University of Messina, Contrada di Dio, 98158 Sant’Agata, Messina, Italy

* Corresponding author. Tel.:+39-347-412-1215. E-mail address: mariagiovanna.tanda@unipr.it

2452-3216 © 2026 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the Conference 10.1016/j.prostr.2026.06.036