Modular maintenance

The Geoga Bridge in South Korea, equipped with TENSA®MODULAR expansion joints in advance of its opening in 2010, is currently having the elastomeric and sliding components of the joints replaced to optimise their ongoing performance.

Even the best expansion joints on the market require maintenance at times, and this is especially true of complex joint designs such as TENSA®MODULAR – a product that offers extraordinary flexibility thanks to its “elastic design”, thereby preventing restraint forces from arising and thus improving the joint’s long-term performance. However, the elastomeric and sliding components that provide this flexibility are not as durable as the main steel elements, and may require replacement at some point during the joint’s service life. Thanks to mageba’s continuous product development since inventing the modular expansion joint in 1965, the components offer extraordinary durability considering the many millions of movements and forces to which they can be subjected, and they can be quite easily replaced when the time comes to do so.

This is currently being demonstrated on the Geoga Bridge in South Korea, which was equipped with TENSA®MODULAR expansion joints during its construction – the largest 15-gap joints accommodating longitudinal movements of 1200 mm as well as transverse/vertical movements and triaxial rotations. Due to the enormous traffic volumes on this bridge and the aggressive marine environment, the non-steel components that accommodate continual movements and rotations began to show signs of deterioration.

To optimize the efficiency of replacement works while ensuring excellent ongoing long-term performance, it was decided to replace all the non-steel components at once. This is far quicker and easier, minimizes costs and reduces the impact on bridge users due to traffic disruption.

The work is now almost complete, leaving the expansion joints of this important transportation connection in excellent condition – almost as good as when they left mageba’s Shanghai factory over 15 years ago!

Contractor: GK Fixed Link Corp.

The Geoga Bridge in South Korea was equipped with TENSA®MODULAR expansion joints in advance of its opening in 2010

The bridge’s exceptionally flexible TENSA®MODULAR expansion joints facilitate large longitudinal movements (up to 1200 mm) while also accommodating transverse and vertical movements as well as triaxial rotations

Rather than replacing the entire expansion joints, mageba proposed a far quicker and easier solution that would minimise impacts on the bridge’s users – replacing only the non-steel components that facilitate movements and rotations

On the surface of each expansion joint, the rubber sealing strips that connect the individual steel surface beams – to make the expansion joint watertight – have already been replaced

Beneath the surface, the elastomeric and sliding components (various springs and bearings) are currently being replaced

Thanks to the approach taken, which minimises costs and traffic disruption, the condition of the expansion joints of this crucial bridge will soon be almost as good as when they left mageba’s factory over 15 years ago