Twin Sails Bridge, United Kingdom

The Twin Sails Bridge is a lifting bridge that spans the backwater channel in Holes Bay and connects Poole town centre to Hamworthy. It will be the second harbour crossing at the Holes bay.

The existing bridge, which was built in 1927, is facing congestion due to increasing traffic levels. The new bridge is expected to ease congestion.

The bridge got its name Twin Sails due to the sail-like appearance of the triangular lifting leaves. The construction works were initiated in May 2010 and the bridge is expected to be opened to traffic in the first half of 2012. The project is estimated to cost £37m.

The new bridge will be linked to the West Quay Road in the east and urban feeder roads in the West.

The old bridge will continue to operate even after the opening of the new bridge.

Design of the Twin Sails Bridge

The Twin Sails Bridge is a double leaved bascule bridge. The leaves are lifted at 88 degrees with the help of hydraulic rams so ships can pass through easily.

The bridge will include two sections of bridge deck composed of 41 steel sections and two sections of walkway. It will be about 139m long and consist of five spans.

The approaches comprise two spans of approximately 27m each on either side of the opening span. The central area will consist of two triangular lifting leaves. When open these leaves will be 35m above the bridge deck.

The bridge comprises a 10.8m wide carriageway providing two traffic lanes and 2.0m wide cycleways along both edges of the carriageway. The bridge also carries two 2.5m wide pedestrian footpaths.

Construction of the lifting bridge

The plan for the construction of a new harbour crossing was initiated in the 1980s but first proposed in 2004. The Twin Bridge received an approval from the Secretary of State for Transport in August 2006.

The construction was put on hold in 2007 due to issues between the council and the land owners. A contract signed between the council and the landowners in August 2009 allowed construction to start.

Construction work on the bridge at Poole Harbour began in May 2010 but was delayed until October 2010. The construction will take around 20 months to complete.

Construction of the junction which will link the bridge to the Blandford Road began in January 2011.

The demolishing works on Poole Boat Park building started in June 2011. The work on the installation of six supports of the bridge began in October 2010.

Deliveries of the steel work required for the bridge construction began in March 2011. The first of the two lifting leaves weighing 65t each was delivered in April 2011. The lifting leaves were installed in place in July 2011.

Contractors involved in the construction project

Hochtief (UK) Construction won the £18.5m contract for the construction of the bridge. The contract for the supply of around 900t of steel has been awarded to Cleveland Bridge UK. Gifford, part of Ramboll, are the lead design consultants.

Speirs and Major Associates will design the bridge lighting works.

Construction of new roads and footpaths to link the bridge to Blandford Road will be taken up by the landowners JJ Gallagher and Land Improvement Holdings.

Financing the Twin Sails Bridge

A loan of £9.96m was granted towards the project by the South West of England Regional Development Agency in March 2010. The Department of Transport funded £14.1m in February 2010.

The project has also received funding from the Department Communities and Local Government (£2m), Borough of Poole (£7.939m) and Developer Contributions (£2m).