Derbyshire County Council
Butterley Station overbridge has a 15m span deck with eight riveted steel girders spanning onto concrete abutments.
The existing rocker bearings were badly corroded and required replacing. The new pot bearings were manufactured by Freyssinet about included 14 free slidings bearings, one fixed bearing and one guided bearing.
The bridge abutment was deep enough that the 260 ton pot ram jacks could fit with only local modification of the abutment. The deck was lifted by only 2mm, controlled by dial displacement gauges, with no more than 0.5mm difference between adjacent beams. Once the load had been relieved from the original bearings, the concrete around them was removed by one of the Freyssinet’s in-house hydrodemolition team. Fast setting, high strength grout and concrete was then used to bed in the new bearings.
Works also included the removal of the concrete casement to the main steel girders where it had cracked by hand breaker. The steel girder was cleaned back to metal and epoxy corrosion protection applied before finishing off with new hand-applied repair mortar. The work beneath the bridge required Freyssinet to remove the existing smoke deflection barriers and these were replaced with new stainless steel baffles. Above the deck, brickwork repair to the parapets and pilasters, resurfacing works to carriageways and footways and replacement of the bridge deck joint completed the job.
Freyssinet is able to offer inspection, design, manufacture, testing and installation of bridge bearings. Click here for more information.