Indian expertise

The engineers of mageba’s office and factory in Kolkata lend their know-how and experience to the challenging replacement of bearings of two railway bridges in the Indian state of Goa.

Having delivered sophisticated structural bearing and expansion joint solutions to various bridges across the sub-continent for many years already, our team in India has extensive experience in the supply of bearings for impressive railway bridges such as the Chenab Railway Bridge, the New Jubilee Bridge at Kolkata, the Hyderabad Metro’s viaducts and the two-level road and rail bridges over the Ganges River at Munger and Patna – among many others.

But an extra degree of expertise is called for when the task is to replace bearings in an existing structure, considering the need for the new bearings to precisely match the old ones in certain respects, and the complications of working on a bridge that is already in service.

In the case of the recent project to replace the bearings of the main span structures of two railway bridges in western India – on the Zuari and Mandovi rivers – a major challenge was presented by the severely limited track closures during which work could be carried out (maximum 3 hours, sometimes only 1.5 hours). Another significant challenge was the difficult access to the pier tops.

After evaluating the situation in detail, mageba proposed a complete solution involving the design and manufacture of suitably dimensioned and detailed RESTON® POT bearings, the construction of a temporary access platform at each pier to facilitate the installation work, lifting of the bridge superstructures using specially designed low-height hydraulic jacks, and injection of rapid-cure grout beneath the new bearings to ensure proper transfer of load to the substructures.

Executing the work properly, efficiently and safely during the very limited track closures required detailed planning, close coordination with the railway company, and a great deal of engineering competence. Thankfully the work has been completed on both structures without incident, and our colleagues are already applying their expertise to other challenging projects around the country.

Contractor: Afcons Infrastructure Ltd.
Owner: Konkan Railway Corporation

The Zuari Railway Bridge in the western Indian state of Goa, which required the bearings supporting its steelwork superstructure to be replaced

The Mandovi Railway Bridge’s steelwork main span also required its bearings to be replaced, presenting a similar challenge as the Zuari Railway Bridge

The bearings to be replaced were in hard-to-access locations – high above the water in the middle of a wide river

Temporary platforms also had to be constructed to facilitate the replacement work since the bearings were high above the tops of the bridge piers

View of one bridge bearing before it was replaced

The existing structural bearings were in a poor state after many years of service

Transportation – during one of the short track closures available – of two bearings required for one bridge

Lifting of the bridge superstructures was done using a pair of closely coordinated hydraulic jacks

Lowering a new bearing into position beside the existing bearing that is to be replaced

Pulling out of an existing bearing after removal of all connection bolts and lifting of the superstructure

Cleaning and preparation of the main structure to receive the new bearing at one location, including application of corrosion protection

A special high-performance metal plastic grout – high strength, quickly applied and fast curing – was injected beneath the bearings to ensure proper transmission of forces to the substructures