Temporary Protection Deck
Chislehurst Road Bridge carries the A208 between Chislehurst and Orpington in Kent. The existing post tensioned, reinforced concrete bridge was to be replaced by a new steel plate girder bridge. Located over four lines of busy railway meant construction and demolition activities needed to be undertaken in such a manner to ensure its continued safe operation.
In conjunction with Hochtief, Crouch Waterfall created an innovative temporary works design solution incorporating a 31 metre span, 300 tonne steel and timber protection deck providing a rigid platform that enabled construction activities to be undertaken with only minimal disruption to the railway.
Continuous slide path beams were installed at three locations below the bridge. Long span steel beams, decked out in timber, were placed onto these slide paths in braced pairs by crane. The beams were then slid into position below the deck using strand jacks until a continuous platform was formed. Once in position the deck was then jacked vertically from positions adjacent to the slide paths to give a tight bearing against the underside of the existing bridge and prevent any potential for dynamic loading during demolition. The protection deck would be jacked back down and utilised as a working platform for progressing further construction activities.