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The New Kelani River Bridge, recently constructed in the island nation of Sri Lanka, is the country’s first extradosed bridge – combining the main elements of a prestressed box girder bridge and a cable-stayed bridge but with the "stay cables" treated as external prestressing tendons. It is one of Sri Lanka’s finest bridge structures, and has been constructed accordingly with high-quality components. The bridge was built to cross the Kelani River in the capital city, Colombo, connecting to the main expressway serving the international airport. The structure has a main span of length 180m and outer spans of 100m each, and the construction was done using the balanced cantilever method.
After a very detailed selection process that lasted about four years, mageba was chosen to supply the expansion joints required by the structure, to be of the cantilever finger type. Six TENSA®FINGER type RSFD joints were designed to suit the structure’s particular needs in accordance with relevant Japanese (JIS) and American (AASHTO) standards, and to facilitate movements of up to 300 mm.
A unique feature of the expansion joints is the secondary elastic seal that has been integrated into their design in accordance with client specifications. As a result, the watertightness of each joint is ensured not only by the drainage channel that hangs beneath the joint (like all TENSA®FINGER joints), but also by a strip of compressible watertight material just below the joint’s surface plates. The addition of this second line of defence against leaks required the design and fabrication of the joint to be adapted accordingly.
Another notable aspect of the project – and a significant challenge – was the transportation of the joints from mageba’s Kolkata factory to the bridge construction site in Colombo. Since each joint was too long to be transported in a closed shipping container – our preferred method where lengths allow in order to minimise shipping delays and avoid the risk of damage – they were transported all the way from Kolkata to Colombo on a flat bed truck which made the crossing from southern India to Sri Lanka on a ferry.
Having previously supplied structural bearings and expansion joints for a number of particularly noteworthy projects in Sri Lanka – including major infrastructure projects such as the Central Expressway Project which required close to 2000 LASTO®BLOCK elastomeric bearings, and landmark building projects such as the striking new ITC Colombo One building in the capital city – it seems that mageba is earning a reputation there as the go-to supplier where something out of the ordinary is needed. And we are always happy to oblige.
Bridge designer: Oriental Consultants Company Limited and Katahira Engineers
Contractor: Sumitomo Mitsui Construction Co. Ltd. - Sanken JV
Owner: Road Development Authority of Sri Lanka