Special needs

With innovation at its core, mageba has always risen to the challenge of providing structural bearing and expansion joint solutions to the unique demands of bridges all around the world – as demonstrated once again in a current bridge construction project in India.

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

The new bridge, due to be inaugurated by the end of this year, has a main span of length 440 m and connects the towns of Dobra and Chanti in the Uttarakhand region of northern India across a Bhagirathi River reservoir

A pinned link / rocker bearing (or “pendel”) during manufacture in mageba’s Kolkata factory

A pinned link / rocker bearing as installed, connected to a steel girder of the superstructure at the top and to a concrete pedestal at the bottom, with anchorages designed to resist tension forces as well as compression forces

3D design representation (cut-out view) of a wind shoe bearing – installed “sideways” to prevent transverse movements of the superstructure

Wind shoe bearings as fabricated, ready to be delivered to site

A 12-gap TENSA® MODULAR expansion joint, designed to accommodate 960 mm of longitudinal movement (as well as other movements and rotations) as installed following fabrication in mageba’s Kolkata factory

Ting Kau Bridge, Hong Kong (1997): A pendel-type “rocker bearing” during fabrication and assembly at mageba’s factory in Switzerland

Irtysh River Bridge, Kazakhstan (1999): A pendel-type “rocker bearing” during production at mageba’s Swiss factory

Irtysh River Bridge, Kazakhstan (1999): A “wind shoe”-type device to prevent transverse deck movements, during production at mageba’s Swiss factory

Oeresund Bridge, Denmark to Sweden (1999): Production in mageba’s Swiss factory of one of the many RESTON® POT bearings (designed for loads of up to 96,000 kN) used in the construction of the bridge

Golden Ears Bridge, Canada (2008): Custom-designed uplift bearings, pre-compressed for frequent load reversal. Each bearing weighs 17 tons and can accommodate a wide range of loads from 4,170 kN to –2,790 kN (uplift), longitudinal movements of 3,100 mm, transverse movements of 50 mm and rotations of 0.039 radians about the x-axis and 0.010 radians about the y-axis

Tran Thi Ly Bridge, Vietnam (2011): Two enormous RESTON® SPHERICAL bridge bearings upon which the inclined pylon of the bridge will be constructed, each designed to support loads of 250,000 kN (three times the weight of the Eiffel Tower) while also allowing sliding movements and resisting transverse forces

Third Bosphorus Bridge, Turkey (2015): Specially developed cylindrical pendulum bearings. In relation to load and displacement, the curved sliding plates of these bearings have extremely small radii in order to stabilise the bridge horizontally under railway traffic. The bearings weigh up to 34 tonnes each, designed for vertical loads of up to 120 MN while facilitating longitudinal movements of +/– 770 mm