CHENNAI: A preliminary inquiry into the collapse of the main carriageway of the bridge on the Villupuram–Nagapattinam stretch of NH-32 at Vallampadugai near Chidambaram has found that the incident was caused by a failure in the foundation caused by inadequate bearing capacity.
The carriageway caved-in by about 2.5m and experienced horizontal movement, posing a threat to nearby buildings. As a precaution, the National Highways Authority of India (NHAI) asked residents of 10 buildings close to the structure to vacate. The bridge has been in use for around 18 months.
Following the incident, toll collection at the Kothattai toll plaza was suspended and traffic diverted. NHAI also issued show-cause notices to the concessionaire and the independent engineer, seeking explanations.
The 400m light vehicular bridge, part of the Kollidam bypass in the Poondiyankuppam–Sattanathapuram section, was built in 2023 and opened to traffic in March 2024.
Officials said routine inspections on March 20 and 21 did not reveal defects. However, on April 4, cracks in the pavement quality concrete and sinking by about 100 mm over a 30-metre stretch were noticed. During repairs, further damage was detected early on April 6.
Subsequent inspections found bulging, cracking and horizontal displacement of ramp wall blocks over 50m. An official said the approach ramp had caved in by 2.5m but the movement stabilised by Tuesday. A team of experts has been deployed for a detailed study. The damaged portion will be removed and rebuilt, and remedial measures implemented to restore traffic at the earliest.