Korean innovation

Faced with the challenge of refurbishing the old modular expansion joints of a major suspension bridge, our team in South Korea developed a new method that involves replacing only the surface beams – minimising impacts on the structure and on traffic.

Construction of the Yeongjong Bridge in South Korea was completed in the year 2000 to provide road and railway access to the new Incheon International Airport – the main airport serving the capital city, Seoul – which is located on an island off the country’s west coast. mageba was honoured to be entrusted with the job of supplying the 8-gap TENSA®MODULAR expansion joints used in the construction of this spectacular two-level suspension bridge. Eight years later, we took it as confirmation of the expansion joints’ very good performance to date when we were selected to supply joints of the same type (this time with up to 24 gaps each!) when the equally impressive Incheon Grand Bridge was constructed to provide a second highway connection to the airport island.

After more than two decades of service, under extremely heavy traffic and subjected to the harsh marine environment, the driving surface of the Yeongjong Bridge’s expansion joints had deteriorated from steel corrosion and mageba was contacted to advise how to address the issue. Our team in South Korea, whose office is just south of the capital and equally close to Incheon, assessed the condition of the joints and came up with an approach that would minimise effort, expense and the use of materials and resources – and perhaps most importantly, also minimise the impact on traffic while the work was carried out.

Since the expansion joints were still in good condition apart from the corrosion of the driving surface, our dedicated engineers developed an innovative solution, illustrated by the photographs, that essentially involves replacing the surface beams only. This approach is less invasive than the ”box-in-box” method, developed by mageba years before, which involves also replacing the support bars beneath the surface beams. While it is more invasive than the Quick-Ex method, that option only exists where an expansion joint has originally been fabricated and installed with mageba’s Quick-Ex design, which had not yet been invented at the time of the Yeongjong Bridge’s construction.

The range of solutions developed by mageba to provide options for modular joint renewal demonstrates the innovativeness and engineering capabilities of our teams all around the world – if there is a way of minimising the cost, effort or side effects of expansion joint replacement work on your structure, we will find it for you!

Bridge engineer: Yooshin Engineering Corporation & CHODAI CO.,LTD.
Owner: The New Airport Hiway Co., Ltd.

The Yeongjong Bridge in South Korea was constructed in the 1990s, using mageba TENSA®MODULAR expansion joints, to provide road and railway access to the island on which Seoul’s main airport, Incheon International, was being constructed

Eight years after the Yeongjong Bridge was built, the Incheon Grand Bridge was constructed – also using TENSA®MODULAR expansion joints – to provide a second highway connection to the airport island

The decision to install TENSA®MODULAR expansion joints on the Incheon Grand Bridge – with extraordinarily large 24-gap joints among the 76 expansion joints used – was made following eight years of experience with this joint type on the nearby Yeongjong Bridge

After more than two decades of service under heavy traffic in this demanding marine environment, the expansion joints in question were still in good condition apart from their surface beams which had suffered from corrosion

To avoid replacing more of the joint than was necessary, mageba developed a new refurbishment solution requiring only the surface beams to be renewed – first the edge beams, requiring cutting and welding

Following renewal of the edge beams, the remaining surface beams (the centerbeams) were disconnected from the support bars beneath which span the bridge’s movement gap, and lifted out

View of the bridge gap following renewal of the edge beams and removal of the old centerbeams, showing the support bars which span the bridge’s movement gap and which provide sliding support to the centerbeams via a stirrup connection

New centerbeams were then installed and connected to the support bars beneath, complete with new elastomeric components

Used to refurbish a modular joint that only requires its surface beams to be replaced, this newly developed method avoids unnecessary use of materials and resources while also minimising impacts on the structure and on traffic – a credit to the engineering abilities of our team in South Korea!