PSI - Issue 64

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2023) 000–000

www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 64 (2024) 918–924

SMAR 2024 – 7th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures Welding under service conditions – Monitoring, repair strategy and rehabilitation Julian Unglaub a, *, Florian Begemann a , Jonas Hensel b , Klaus Thiele a a Institute of Steel Structures, Technische Universität Braunschweig, Beethovenstraße 51, 38106 Braunschweig, Germany b Institute of Joining and Assembly, Chemnitz University of Technology, Reichenhainer Straße 70, 09126 Chemnitz, Germany Abstract Steel structures, such as bridges, must be continuously maintained. Many steel bridges are subject to various types of damage, such as cracking, due to increasing traffic loads, design and construction deficiencies. To address these problems, it is necessary to perform maintenance, typically by removing these cracks by re-welding. During this repair process, the affected bridge needs to be closed to traffic in order to prevent crack movement during the welding. Due to this closure, traffic is diverted to alternate routes, increasing the traffic loads on those routes, which, unfortunately leads to additional damage and subsequent welding work and costs for these alternate structures. Therefore, the primary goal is to establish a method that allows welding work on steel structures while traffic is running. In order to achieve this, measurements were initially taken at a representative steel bridge in order to ascertain the parameters of amplitude and frequency associated with the opening of the gap for the purposes of conducting welding tests under cyclic loading conditions. Subsequently the weld quality and the fatigue performance were quantified. The weld quality and the fatigue strength met the standard requirements, allowing for welding under service conditions, subject to certain conditions. In this paper, it will be presented which crack monitoring techniques can be used to quantify the gap opening. A repair strategy for butt joints is presented, along with data on the fatigue strengths achieved. It is also shown how this repair process can be documented in a digital twin framework. © 2024 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 SMAR 2024 Organizers Keywords: repair of bridges; retrofitting, fatigue; structural health monitoring; digital twin © 2024 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 SMAR 2024 Organizers

* Corresponding author. Tel.: +49 531 391 3375; fax: +49 531 391 4592. E-mail address: j.unglaub@stahlbau.tu-braunschweig.de

2452-3216 © 2024 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 SMAR 2024 Organizers

2452-3216 © 2024 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 SMAR 2024 Organizers 10.1016/j.prostr.2024.09.367