thumb_pic2Concrete Cyclebridge over pedestrian underpass

Asda were building a new store in Melksham and this created the need for many road improvements in the area. These improvements included the creation of a combined footway and cycleway adjacent to the busy A350.

A pedestrian underpass existed under the A350 and the new cycleway had to cross the approach to the underpass. Available headroom was tight so any new bridge needed to be shallow in construction depth. It was decided that a shallow concrete "T" beam was used, at only 250mm deep and 3m clear width. The overall length of the new bridge is 5.6m.  The bridge was cast in our own concrete works and weighed 9t complete with parapets.

The bridge was to bear on existing retaining walls which formed part of the approach to the subway. We cut a slot into the top of the retaining walls then drilled and chemically anchored reinforcement. A new bearing plinth and ballast wall was then cast on top. Pedestrian management was critical as it was not possible to close the subway. A scaffold was erected with screens to protect the passing public.

Erection of the bridge was undertaken by positioning a small crane in a lane closure. The crane lifted the new deck, complete with the 1.4m high cycleway parapet already erected, directly from the delivery vehicle onto the foundation, an operation that took less than one hour.

To ensure continuity of waterproofing over the lifting points, the anti-slip surfacing material was applied after erection using Stirling Lloyd "Bridgemaster"

Construction of the new road layout, pedestrian footpath and cycleway and the new Asda store were all completed on time.