NHAI Floats Rs. 105.7 mn Tender to Repair 12 NH 32 Bridges
The affected structures are located at Palliodaivayal, Marudangavayal, Vallikkollaikadu, Maravanvayal, Manamelkudi, Kottaipattinam, Periyamadaippaychchal, Nattanipurasakudi, Kanatangudi, A Manakudi and Chitturuvadi. The audit was carried out for the NHAI’s Ramanathapuram Project Implementation Unit by a private consultancy.
The inspection included non-destructive tests such as Ultrasonic Pulse Velocity, Rebound Hammer and Half-Cell Potential testing. Several bridge components recorded low or doubtful ultrasonic pulse velocity readings, pointing to internal cracks, voids and weakened concrete integrity. Half-Cell Potential results indicated a high probability of reinforcement corrosion, while chemical testing detected carbonation of the concrete.
Physical inspections found exposed and heavily corroded reinforcement, loss of rebar cross-section caused by rusting, cracked and debonded protective concrete layers, and spalling. Bearings at some locations were corroded and seized. Expansion joints at several bridges were clogged with debris and vegetation, affecting drainage and causing water seepage, efflorescence and salt deposits on structural components.
The proposed works include removing deteriorated concrete, treating and strengthening corroded reinforcement, pressure-grouting cracks, jacketing piers and other structural elements with concrete, and applying carbon fibre reinforced polymer to vulnerable members. Consultants have recommended temporary structural propping before major repairs, especially during the removal of damaged concrete from load-bearing components. Static deflection load testing will also be conducted after rehabilitation, before the bridges are cleared for heavy traffic.