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The present report includes the results obtained from a literature survey about corrosion-induced failures of post-tensioned bridges and a few other cases of prestressed structures.
The structures have been briefly described with a focus on the prestressing system. After that, the failures have been characterized according to the severity of the o...
Citations
... In 1992, the Melle bridge spanning the River Schelde in Belgium collapsed unexpectedly due to corrosion of the PT tendons (Concrete Society, 2010;Tilly, 2002). In the USA, investigations revealed corrosion related tendon failures in Florida's Sunshine Skyway bridge, Niles Channel bridge, and Mid-bay bridge (Menga et al., 2022). Such incidents with PT bridges around world pushed international bodies to act such as the Fédération ...
... Although the structure was a cable-stayed bridge, the collapse had likely occurred due to corrosion-induced deterioration of the concrete-encased bridge stays, making the case a relevant example for PT failures (Menga et al., 2022). ...
... Fundamentally, PT systems fail as a result of either being subjected to loads beyond which it was designed for, or, more commonly, when corrosion-induced section loss of PT strands lead to reduction in their capacity (Martin et al., 2001). Corrosion of strands are normally a product of defects left in the system from construction (Menga et al., 2022). One such defect are voids in ducts, and they mostly form due to insufficient grouting or because of grout bleeding (Lau and Lasa, 2016). ...
Post-tensioning systems are a relatively recent technology compared to reinforced concrete, having emerged around the mid-twentieth century, and being widely used in bridge construction ever since. Post-tensioned (PT) bridge designs are often desirable by both designers and contractors since they can economically span long distances whilst providing an aesthetically pleasing structure, they greatly increase structural capacities, and are relatively easy to construct. In the 1960s, it was believed that PT bridges and systems were maintenance free, with a predicted service life of 120 years. This belief was put into question in 1967 with the sudden collapse of the 15-year-old Bickton Meadows segmental bridge in Hampshire, raising concerns about the durability of PT bridges. Therefore, in order to uphold public safety as well as structural integrity of PT bridges, it is imperative that reliable non-destructive damage detection methodologies to assess the health of PT systems are established. Nondestructive testing (NDT) can provide valuable insights into the condition post-tensioned bridges, especially the post-tensioned tendons, allowing for preventative measures to be taken to prevent further deterioration. NDT of PT bridges is often regarded as challenging, with visual inspection alone not being sufficient or possible for some PT bridges such as those with internal tendons. There are a number of NDT methods practiced today, with each method having its potential benefits and drawbacks. This paper carries out a systematic literature review, collecting all the relevant literature related to NDT methods and approaches, both conventional and novel. Using these, selected conventional approaches deemed to be applicable to PT bridges are evaluated, discussing their individual applications, advantages, and disadvantage. These include visual inspection, acoustic sounding, impact-echo, impulse response, acoustic emissions monitoring, infrared thermography, ground penetrating radar, magnetic flux leakage, radiography, and ultrasonic techniques. Some novel approaches introduced in the report are electrical capacitance thermography, the use of unmanned aerial vehicles in NDT, and innovations made in NDT using artificial intelligence and machine learning.
... The main aim of this paper is therefore to present the results of an extensive literature review about corrosioninduced failures of posttensioned bridges conducted by the authors. 23 This paper is meant to be a more approachable and concise summary of the information and comments reported in reference 23, with the aim of reaching more people. Therefore, the details about the structures and the analyses here presented can be found in reference 23, which includes three appendices containing summary tables of the data and pictures collected for each structure in the literature review. ...
... To answer the above questions, a literature survey of corrosion-induced damages and failures in prestressed structures was carried out. 23 The survey consisted in the analysis of all the publicly available documents on the topic to the authors' knowledge (papers and case-studies). ...
... For the other half, they were partly not detected or no information about them was reported in the literature. The analyses conducted by the authors 23 indicate that detection of warning signs can help limit and reduce the damage, provided some conditions are fulfilled: ...
Corrosion of posttensioned bridges raises great concern, since the only way to safely assess the condition of the tendons is through destructive evaluation. In this scenario, this paper presents the results of an extensive literature review on reported cases of corrosion of posttensioned bridges and few prestressed structures. The aim is to increase knowledge about the structural consequences of possible corrosion-induced failure mechanisms. The cases were rated according to the increasing severity of the observed damage and consequent interventions as follows: ordinary maintenance is effective, extraordinary maintenance is necessary, and maintenance is insufficient or absent. It was found that most corrosion-sensitive structures were segmental and box
section beam bridges. Most cases required extraordinary maintenance. Warning signs were often observed. The damage was mainly ascribed to design and execution mistakes that facilitated the ingress of external chlorides causing corrosion. The paper concludes with a discussion of the consequences for structural safety.
This paper presents a risk assessment approach to assist with decision making regarding corrosion protection strategies to be utilized in the design of PT tendons. The risk assessment prioritizes the needs for protective technologies and processes considering the likelihood and consequences of corrosion damage (i.e., the risk). The methodology considers the attributes of different design, specifications, and quality choices made during project development and design. PT system attributes that affect the likelihood of corrosion damage such as tendon profile, alignment, protection, environment, and the quality processes planned for use during construction, are considered. The consequences of corrosion damage resulting in tendon failure are considered in terms of structural reliability, ease of tendon replacement, and the overall importance of a bridge. A simple scoring methodology based on qualitative scales is used to provide a risk score for individual tendons based on its attributes. A sensitivity study was used to adjust weights to individual attributes and define moderate and elevated risk profiles. The study showed that scores of 20–40 pts represented moderate elevated risk and scores of 40 pts or greater represented elevated risk. Methods for risk mitigation and risk reduction are recommended based on the risk model scores.KeywordsRiskPost-TensionedTendonsCorrosionBridges
