PSI - Issue 52

Sairam Neridu et al. / Procedia Structural Integrity 52 (2024) 267–279 Sairam Neridu/ Structural Integrity Procedia 00 (2019) 000 – 000

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this period. The study emphasised the distinct pattern of bridge failures in India, their impact on the economy, and socio-economic disturbances. The most common materials used for bridge construction in India were reinforced concrete (RC) and prestressed concrete (PSC), and the superstructure was the most affected component in failed bridges. The study attributed natural disasters, particularly hydraulic-induced events, as the primary cause of bridge failures. The study also highlighted unique failure patterns associated with different materials and construction processes. Researchers have explored the various types of damages and distress that can occur in RC bridges. M. C. Griffith et al. (2004) found that cracks can form in concrete due to shrinkage, temperature changes, or excessive loads, which can also lead to spalling or corrosion. L. Torres et al. (2016) noted that reinforcement corrosion can occur due to exposure to moisture, salt, or other chemicals, resulting in steel cross-section loss, reduction in bond strength between reinforcement and concrete, and cracking or spalling of the concrete cover. 3. Methodology The methodology employed in the investigation process involved a systematic procedure, as depicted in figure 1. The steps taken included: a) Collecting all available information about the bridge, including design plans, construction records, material testing reports, and maintenance logs of the past. b) Conducting a thorough visual inspection of the bridge, looking for any visible signs of damage or deterioration. This may include cracks, spalling, delamination, corrosion, and other forms of distress. c) Utilizing non-destructive testing methods such as ultrasonic testing, magnetic particle inspection, or ground-penetrating radar to detect hidden defects in the concrete or reinforcement. d) Testing samples of the concrete and reinforcement for strength, durability, and other properties to determine if they meet the required specifications. e) Reviewing the design and construction practices used for the bridge to determine if there were any deviations from industry standards or best practices. f) Considering the environmental factors that may have contributed to the failure, such as freeze-thaw cycles, salt exposure, or seismic activity. g) Reviewing the maintenance practices used for the bridge to determine if they were adequate and timely. h) Analysing all the data collected to identify the root cause or causes of the failure. i) Develop recommendations to prevent future failures, including changes to design standards, construction practices, material specifications, or maintenance procedures. j) Implementing the recommendations to ensure the safety and reliability of the bridge. similar methodologies have been employed in various studies by Behzadfar et al. (2020), and Abu et al (2018).

Fig. 1. Sequence of Investigating the Causes of New Highway Concrete Bridge Failures .

4. Case Study This study presents a case analysis of a minor box-type bridge with two 4-meter spans, measuring 4 meters in height and 16 meters in width as shown in Figure 2. The bridge is supported by a pier wall with a thickness of 300 mm, a deck slab, and a bottom raft with a thickness of 400 mm. Construction involved the use of M30 grade concrete, selected according to design specifications. During the investigation, vertical cracks with a width greater than 0.3mm were observed on both sides of the pier wall, extending from the deck slab to the bottom raft as shown in figure 3. Cracks were detected at 5.7m and 6.0m from the upstream and downstream side edges, respectively, while patchwork and honeycombs were observed on the piers and abutments. Table 1 provides detailed information on the location, width, depth, and remarks of the observed cracks, which were used to evaluate the structural integrity and safety of the wall pier.