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Thinking outside the box
A project to replace or refurbish the bearings of a bridge near Lucerne in Switzerland required ingenuity to come up with a solution to the lack of space on top of some bridge piers – space that was needed to position the hydraulic jacks for lifting the superstructure.
Lifting a bridge superstructure to enable its bearings to be replaced or refurbished, while the bridge remains open to traffic, is generally a challenging task – but nothing our Swiss installation team can’t handle, as they proved again in their recent project at the Grüeblischachen Bridge (01 East and 02 West) in Emmen. This twin highway crossing required 22 of its existing pot bearings to be refurbished (including replacement of their PTFE sliding surfaces and renewal of their corrosion protection), and seven other bearings to be completely replaced.
The biggest challenge was presented by the bridge bearings on slender piers in the middle of a river, where access was particularly difficult. But some extra creativity was still needed to find a way to lift the superstructure at these piers because adequate space was not available on top of each pier to place the required hydraulic jacks.
A special solution had to be developed, which involved designing and fabricating a steel “clamp” to be placed around the top part of each pier with its semi-circular parts bolted together to form a strong circular unit. Following backfilling with grouting mortar, the huge steel clamps were kept in place by friction against the concrete pier, thanks to the tension in the bolts. These steel clamps then supported the hydraulic jacks that lifted the bridge superstructure, enabling the old bearings to be replaced or refurbished.
A clever solution to an interesting challenge!
Client’s engineer: dsp Ingenieure + Planer AG
Owner: Federal Roads Office FEDRO, Zofingen
Contractor: Anliker AG Bauunternehmung
