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The Älvsborg Bridge, built between 1963 and 1966, is a suspension bridge in Gothenburg, Sweden, connecting the north and south parts of the city across the Göta Älv river. The bridge has a total length of 933 m and a main span of 417 m.
To support the planning of bridge renovation works, including the replacement of critical components such as the large sliding finger joints at each abutment, the use of a structural health monitoring system was proposed - in particular, to quantify the structure’s actual movements and rotations, enabling the selection and design of new expansion joints to be optimised.
In the course of recent renovation works the bridge required to have its many small-movement expansion joints replaced. An expansion joint solution that would reliably meet the project’s demanding requirements was needed. With approximately 80,000 vehicles per day crossing the bridge, it is a critical structure for the whole region and therefore it was essential that the new expansion joints could be installed with minimal impact on traffic throughout the whole project.
A ROBO-CONTROL “Permanent” SHM system was installed in 2011, with a network of sensors providing precise records of all movements and giving a detailed understanding of the bridge’s structural behaviour.
The data was used to conclude that bridge movements are less than had been expected. Such information was of great value to the bridge engineer in optimising the planning of the bridge renovation works, particularly in relation to the selection and design of the new expansion joints. The recorded data will also serve as a reference for future analysis and modification work.
From 2016 to 2021 mageba supplied approx. 1’700 m of flexible expansion joints with a movement capacity of 30 mm and adapted to suit the bridge’s road surfacing depth of 65 mm. The joints were installed by the contractor, under mageba supervision, at 26 bridge axes, with each joint installed in four sections, lange by lane, to suit traffic phasing.
The PU joint offers exceptional flexibility in terms of geometry as well – e.g. where upstands, kerbs, bends or junctions are required
ROBO-CONTROL permanent “Advanced” SHM system, TENSA®POLYFLEX® Advanced PU flexible plug expansion joints
2011 / 2016–2021
City of Gothenburg