Karnataka Public Works Department on July 16 achieved a major feat by restoring a semi-collapsed concrete slab of the bridge across Phalguni (Gurupura) river on the road from Mangaluru to the airport a month after it was displaced.
One of the slabs of the bridge at Maravoor sunk a few feet in the early morning of June 15, prompting authorities to prohibit movement of vehicles. Motorists heading to the airport as well as Kateel were told to take alternative routes.
PWD Executive Engineer, Mangaluru, Yashavanth Kumar told The Hindu that the slab had sunk about 2.5 feet. It was lifted to its original position using state-of-the-art equipment and technology. Work on complete restoration of the bridge was being carried out on a war footing. The bridge would be re-opened for traffic by installing necessary safety equipment and conducting load tests, he said adding the work would take about two weeks.
PWD Assistant Executive Engineer K.T. Chandrashekharaiah said, at times, over one hundred men worked day and night to restore the slab to its original position. The Well Foundation (comprising two ‘D’ type structures) that was laid up to a depth of 10 metres had sunk as it was not placed on hard rock.
With expert advice from R.K. Jaigopal, Managing Director of Struct Geotech Research Laboratories Pvt. Ltd., Bengaluru, PWD executed the challenging restoration work. The foundation was initially stabilised with boulders, sand dredging and sand blasting. River water was diverted from the location by building a coffer dam.
The bridge is on the route from Mangaluru city to the international airport. Motorists were told to take alternative routes while the bridge is being repaired.
After strengthening the foundation, work of lifting the slab using sophisticated jacks and expansion joints was carried out. Pedestal caps were installed, and bearings were placed carefully on them to support the slab. Before allowing traffic on the bridge, load testing over 40 tonnes would be carried out to test the work. Mr. Chandrashekharaiah said.
The department intends to keep the bridge in service even after completion of the new parallel bridge that is under construction, by suitably strengthening the foundations of other piers too, he added.
