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At mageba, we manufacture tens of thousands of key bridge components every year to transfer loads and accommodate movements and rotations in structures all around the world. The vast majority of these are from our range of standard products, which has been continually developed over the years to readily address the needs of almost any structure. Although most of the components supplied each year require some degree of project-specific design and engineering, they are still based on designs that have been highly standardised – which of course has many advantages for supplier and user. Sometimes, however, projects come along that have “special needs” – that stray further from the standard than usual, and give us a chance to do real product development work.
In the case of the new Dobra-Chanti Bridge over the reservoir formed by a dam on the Bhagirathi River in northern India – a bridge that saves a 100-kilometre detour for locals since a pre-existing bridge was submerged when the dam was constructed downstream – a wide range of products was required in its recent construction. These products, all supplied by mageba, included some that are used on thousands of bridges every year, such as the 12-gap TENSA® MODULAR expansion joints at each end of the deck to accommodate movements and rotations, and the RESTON® POT bearings that support the approach structures. Less commonly used are the type of LASTO® BLOCK elastomeric bearing (type “KGa”) that have been installed “vertically” as wind shoe bearings in the bridge to prevent transverse deck movements (resisting forces of 1,000 kN) while allowing 960 mm of longitudinal movement. And very rarely have we been asked to supply vertical “pinned link” support struts (also known as “pendels”, “link shoe bearings” or “rocker bearings”) of the type required by the bridge’s design. These units, installed below the deck at the tower locations, had to be designed to resist both downward and uplift forces (with frequent load reversals making fatigue relevant), and to accommodate large superstructure movements and rotations. But having previously supplied similar solutions for the Ting Kau Bridge in Hong Kong (1997) and the Irtysh River Bridge in Kazakhstan (1999), mageba was in a good position to tackle this challenge as well.
At mageba, we relish any chance we get to go beyond the “normal” of our experience to date – as shown by some examples of specially developed bearing-type solutions in the attached pictures. So don’t hesitate to contact us when a project you are working on has special needs – as proven time and again throughout mageba’s history, we will step up to the mark and develop a solution based on our vast experience of products and technologies in delivering a solution that works for you.
Bridge designer: Yooshin Co. Ltd (South Korea) & VKS Infratech Management Pvt Ltd. JV (India)
Contractor: VK Gupta and Associates
Client: Public Works Department, Uttarakhand