PSI - Issue 28

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000–000

www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 28 (2020) 39–44

© 2020 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 European Structural Integrity Society (ESIS) ExCo Abstract The paper approaches the sensitivity to stress corrosion cracking of zinc-coated, high-strength, eutectoid steel wires extracted from collapsed prestressing strands after 30 years of service as tie-down cables of a cable-stayed bridge. The observed damage of wires consisting of pitting corrosion, cross-section losses and even failure, varied in intensity from one cable to another and allowed the assessment of the effect of damage level on the mechanical behavior of wires, as well as that of the susceptibility of the galvanized wires to aggressive environments. The results were obtained by performing fracture tests of service-damaged wires under constant load and under increasing load at low strain rate, while exposed to an aggressive media (ammonium thiocyanate - FIP solution). The SEM analysis of the fracture and lateral surfaces of the tested wires proved the similitude between the service and laboratory-induced damage. It also provided evidence of hydrogen embrittlement in the failure mechanism of the wires. Accordingly, the service ruptures were attributed to progressive cracking by environmentally assisted, hydrogen embrittlement propitiated by the partial dissolution and cracking of the zinc coating in the tensioned wires. © 2020 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 European Structural Integrity Society (ESIS) ExCo Keywords: Prestressing strand; eutectoid steel; stress corrosion; failure mechanism; 1. Introduction The main objectives of present research were to determine the damage process and the fracture mechanisms that induced the failure after 30 years of service of several high-strength seven-wire steel strands in two different tie down cables of a cable-stayed bridge located in Spain. The obtained results serve as reference material to the sets of 1st Virtual European Conference on Fracture Failure cause of bridge tie-down cables after 30 years of service Mihaela Iordachescu a *, Andrés Valiente a , Maricely De Abreu a , Antonio Aznar b a Material Science Dpt., ETSI Caminos, Universidad Politécnica de Madrid, 5 Prof. Aranguren St., 28040-Madrid, Spain b Structures and Building Physics Dpt., ETS Arquitectura, Ciudad Universiatria., 28040-Madrid, Spain Abstract The paper approaches the sensitivity to stress corrosion cracking of zinc-coated, high-strength, eutectoid steel wires extracted from collapsed prestressing strands after 30 years of service as tie-down cables of a cable-stayed bridge. The observed damage of wires consisting of pitting corrosion, cross-section losses and even failure, varied in intensity from one cable to another and allowed the assessment of the effect of damage level on the mechanical behavior of wires, as well as that of the susceptibility of the galvanized wires to aggressive environments. The results were obtained by performing fracture tests of service-damaged wires under constant load and under increasing load at low strain rate, while exposed to an aggressive media (ammonium thiocyanate - FIP solution). The SEM analysis of the fracture and lateral surfaces of the tested wires proved the similitude between the service and laboratory-induced damage. It also provided evidence of hydrogen embrittlement in the failure mechanism of the wires. Accordingly, the service ruptures were attributed to progressive cracking by environmentally assisted, hydrogen embrittlement propitiated by the partial dissolution and cracking of the zinc coating in the tensioned wires. The Authors. Published by ELSE IER B.V. i an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) r-review under responsibility of the European Structural Integrity Society (ESIS) ExCo Keywords: Prestressing strand; eutectoid steel; stress corrosion; failure mechanism; 1. Introduction The main objectives of present research were to determine the damage process and the fracture mechanisms that induced the failure after 30 years of service of several high-strength seven-wire steel strands in two different tie down cables of a cable-stayed bridge located in Spain. The obtained results serve as reference material to the sets of 1st Virtual European Conference on Fracture Failure cause of bridge tie-down cables after 30 years of service Mihaela Iordachescu a *, Andrés Valiente a , Maricely De Abreu a , Antonio Aznar b a Material Science Dpt., ETSI Caminos, Universidad Politécnica de Madrid, 5 Prof. Aranguren St., 28040-Madrid, Spain b Structures and Building Physics Dpt., ETS Arquitectura, Ciudad Universiatria., 28040-Madrid, Spain

* Corresponding author. E-mail address: mihaela.iordachescu@upm.es * Corresponding author. E-mail address: mihaela.iordachescu@upm.es

2452-3216 © 2020 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 European Structural Integrity Society (ESIS) ExCo 2452-3216 © 2020 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 European Structural Integrity Society (ESIS) ExCo

2452-3216 © 2020 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 European Structural Integrity Society (ESIS) ExCo 10.1016/j.prostr.2020.10.006