Client: Island Roads
Contractor: MMC Diving Services
Duration: 14 days
Date posted: 11-03-2019
MMC won the tender for the decommissioning and replacement of two existing foot bridges in Bembridge Harbour on the Isle of Wight. The site is a SSSI and Ramsar site Both the National Trust and Natural England were consulted, as were the local town council. No mechanical machinery or plant could be used and so this had to be done the old-fashioned way using skids, skates and rollers.
Temporary works, including site compound, welfare, bridge transportation systems, temporary scaffold/platforms for substructure repairs, shuttering/formwork and hydraulic jacking systems were required.
The decommissioning and disposal of the old footbridge superstructures required the use of oxyacetylene, basic hand tools, grinders, and included removal from site and disposal, this was all carried out in line with our waste management procedure.
Preparation of existing abutments to found the new bridge decks were undertaken using a bio hydraulic breaker, all debris collected was used on the infill of the existing counter weight pits.
Repairs and alterations were made, including clearing and dewatering of the historic counterweight pits, prior to filling with a lean mix concrete. Due to the structure having damage caused by natural forces, shuttering was required to infill large voids under the footpath approach prior to the new bridge being positioned.
MMC unloaded the new bridges on rollers onto the gated steel "C channel" steels, with 60 ton skates. Motion was then controlled using a winch and X4 gated steels positioned like train tracks, two in front of two. The MMC team pushed the bridge manually from one set of steels onto the next, moving the steels from the back around to the front of the bridge and then repeating the process. Lifting and re-rigging was undertaken using a 10 ton porter-power and a 40 ton air jack.