Case Study One

Project: Balloch Bridge

The existing bridge over the River Leven, which flows from Loch Lomond at Balloch, near Glasgow, was constructed at the beginning of the twentieth century.

Assessment showed that the condition of the existing bridge superstructure was insufficient to support modern day traffic loadings. The assessment indicated however that the existing substructure had sufficient capacity to support a replacement deck.

In addition, the existing bridge has become a popular spot for sightseeing pedestrians who use the bridge to view the scenery surrounding Balloch.

It had become apparent that the widths of the footpaths on the existing bridge were insufficient and the segregation of vehicles and pedestrians was inadequate.

HBPW entered a design competition in conjunction with C Spencer Ltd to provide a replacement for the existing bridge.

The joint proposal was successful both financially and aesthetically and was favoured by senior members of the community of Balloch.

The proposal was to provide a replacement, almost identical bridge that utilised the existing sandstone abutments and river piers.

The proposal received full planning permission including the blessing of Historic Scotland and the National Park Authority within which the bridge fell.

Cantilevering the new footpaths outside the main girders of the bridge provided additional footpath width. This allowed for the increase of road width to acceptable modern standards and the segregation of pedestrians and vehicles.

HBPW has designed and detailed the five span structure in accordance with an agreed Approval in Principle. It is a five span continuous structure with integral abutments and has two principal main girders supporting a composite steel/concrete road deck and cantilevered steel footpaths with aesthetically pleasing handrails.

The design of the bridge was subjected to a Category III design check in accordance with Highways Agency Standard BD2/02.

Main Client: West Dunbartonshire Council
Main Contractor: C Spencer Ltd
Category III Check: Breakwell Sumner Partnership