PSI - Issue 84

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ScienceDirect

Procedia Structural Integrity 84 (2026) 1079–1086

III Fabre Conference: Existing Bridges, Viaducts, and Tunnels: Research, Innovation, and Applications Assessment of bonded post-tensioning in existing concrete bridges

using advanced non-destructive testing techniques Gianni Moor a , Tristan Craig-Tyler a , Colm O'Suilleabhain a ,* a AQUILA Built Health, Ringstrasse 2, 8603 Schwerzenbach, Switzerland

© 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: post-tensioning; grout voids; corrosion; non-destructive testing (NDT); bridges; structures; inspection. Abstract All critical structural systems, including the post-tensioning tendons in concrete bridges, require periodic inspection to ensure they remain safe and functional. Corrosion is the leading cause of degradation in these systems and is difficult to detect when tendons are encased in ducts within concrete. For bonded post-tensioning (where tendon ducts are filled with grout to bond and protect the steel), assessing corrosion risk can be achieved by checking for voids or gaps in the grout that might allow moisture ingress. This paper introduces advanced non-destructive testing (NDT) techniques to locate such grout voids in bonded post-tensioned structures, enabling quicker, less costly and less invasive inspections than traditional methods. 1. Introduction Post-tensioning has long been regarded as a reliable and efficient method for constructing concrete bridges and other long-span structural elements. By applying prestress, it allows for longer spans and more slender components, improving the usability of space. Post-tensioned concrete is also more environmentally friendly than conventionally reinforced concrete, using up to 50% less material and thereby helping to decarbonize the built environment.

* Corresponding author. Tel.: +41 44 258 88 00 E-mail address: colm@aquilabuilthealth.com

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.2026.06.138