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Bridging the gap

A second lifting bridge will soon be a feature of Poole’s skyline. Ally Stratford tells the story of the Twin Sails so far.

The specially commissioned sign above the entrance is completely in keeping with the building

Poole has a good record of regenerating itself. In the 1960s and 1970s the town centre underwent complete re-development as a huge area at the end of the High Street through to the Ladies’ Walking Field was cleared. In its place came a modern shopping centre and arts centre, while a new road system, including Towngate Bridge, transformed the traffic flow.

Today, Poole is preparing for a new project, under the title ‘Full Sail Ahead’, to span the next ten years. An opportunity has been provided by the clearance of the old power station site on the Hamworthy side of the Back Water Channel, which leads from the Quay into Holes Bay, under the existing lifting bridge. This site could provide over 1000 new homes, which will need access to the town centre. At the same time, there has long been a need to improve the reliability of the crossing for traffic to and from Poole Port, some of which at the moment uses the built-up Blandford Road through Hamworthy in preference to the lifting bridge. The project will also provide an opportunity to regenerate the waterfront on the eastern, town side of the Back Water Channel.

Two of the original George Biles murals in the foyer

For thirty years, Poole people have campaigned to ease traffic congestion in the town centre, much of which is caused by the lifting bridge. This was built in 1927, before which the crossing was a privately owned toll bridge. The bridge has seven scheduled lifts a day, with further ‘on-demand’ lifts for commercial vessels. The average lift is six minutes, but during peak times in summer the bridge may be raised for as long as 35 minutes; unfortunately, the summer peak on the water coincides with the summer peak on the roads.

Preliminary investigations and design work began in the 1980s and a proposal for a fixed bridge, spanning the width of Holes Bay and joining the A31, was developed as part of Central Government’s Trunk Road Programme. The government subsequently changed their policies on transport and the plans were dropped. In 2000 the Local Transport Plan compiled by Poole BC, Bournemouth BC and Dorset CC confirmed that a second harbour crossing was needed and therefore a local solution would have to be sought.

A wide range of options was considered, including: upgrading the existing freight-only railway around the bay to carry passengers; a high-level, fixed-link, long bridge across Holes Bay from the power station site to Holes Bay Road; a low-level lifting bridge across Holes Bay from the power station site to Holes Bay Road; long or short tunnels; a high-level, fixed-link, short bridge diagonally across the Back Water Channel, connecting the power station site to West Quay Road; and a lifting dual-carriageway bridge to replace the existing lifting bridge. The preferred option, though, was a low-level lifting bridge on a short route between West Quay Road and the power station site in Hamworthy.

Public exhibitions and consultations began in 2001. Despite the enthusiasm of Poole BC, who saw this as the way forward for the town’s regeneration, there were local people and organisations who were originally opposed to the plans. Some remain that way today. They would argue that the only sensible option was the fixed-link bridge originally submitted to the government. The port brings in much traffic from overseas and they point out that the many lorries en route to and from the harbour are destroying the quality of life in Poole town centre and the surrounding residential areas. A fixed link would have relieved this traffic.

Laurence Anholt’s is just one of a series of wonderful murals by artists connected with West Dorset or the Electric Palace

Another concern is that the location of the new bridge, so close to the existing bridge on the town centre side, will add to the congestion of town centre traffic rather than relieve it. Council planners deny that this will be the case. It has even been said that the project is designed more for the aggrandisement of Poole and the inflation of property values than for the best interests of all the town’s residents; it is difficult to sustain such a view, though, which does scant justice to the efforts of the councillors and officers who have struggled with the intractable problem. It is true that a scheme involving two town centre bridges so close together and without the wider infrastructure required to divert heavy goods traffic is unusual, if not controversial.

By the end of 2001 the council received confirmation of £14.1m funding by the government, but this resource would only be available when a contract to build the bridge was in place. Sixty designs were originally submitted to the council, which were eventually short-listed to three. The following year, Gifford & Partners with Wilkinson Eyre Architects and mechanical engineers Bennett were appointed as the design team for the new bridge. This team were the designers of the award-winning ‘Blinking Eye’ bridge in Gateshead.

They came up with the eye-catching, iconic design that will be a dramatic addition to Poole’s skyline, whilst remaining sympathetic to the environment. The bridge is configured as a simple bascule – a flat deck with two hydraulically operated lifting sections. The joint between each section is skewed across the deck, though, creating two triangular leaves. This creates a unique and exciting visual impact because the leaves cross as they rise and come to rest, mirroring the shape of racing yachts passing through the bridge. As they lift, the bridge becomes a sculptural composition.

The creation of the Twin Sails Bridge, as it has become known, is divided into three phases. The first phase involved the initial design and environmental studies that were needed for permission to build the bridge. In order for the council to get the go-ahead, to obtain the land required and to change the way the existing bridge is operated to allow the two-bridge system to work effectively, a new Transport & Works Act Order had to be granted by the government. This came into force in September 2006.

The Peter Sheridan mural which will be filled in with portraits of real people. The figure in the right foreground is the late Bernard Gale.

The project is currently in the second phase, involving twelve months work on finer design details, procurement, advanced works like the building of an alternative slipway and crucial negotiations with potential developers. The third phase, that is the actual building of the bridge, will require financial contributions from developers who will be linking it with the development of the power station site, together with other sites on the Hamworthy side of the channel. It is estimated that the bridge will take two years to build, so it might open in 2009 or thereabouts.

The Twin Sails Bridge will work in conjunction with the existing lifting bridge. The new system is designed so that one bridge will always be available for traffic into and out of the town centre. Boats will be let through one bridge and will wait in the ‘holding basin’ until one bridge is lowered and the other raised. The waiting time is predicted to be less than half an hour. Motorists will be advised which bridge to use via an electronic system of ‘variable message signage’ in the town and on all the approach roads.

There is local opposition to the ‘holding basin’ approach to maintaining marine traffic through the two bridges. There is less than six feet clearance under the present bridge at high tide and during the busy summer period there can be many boats waiting around for the bridge to open. Currently they all have a large area of water in which to manoeuvre and many wait a considerable distance from the bridge. When there is a strong tide or strong winds, it will be more difficult for these vessels as they will be confined to a smaller area.

The Twin Sails Bridge will be an important landmark structure but it is also essential that the bridge is robust and reliable, having to open hourly and be capable of operating in wind speeds of up to 70 mph. It will carry two vehicle lanes, adjacent cycleways and pedestrian footpaths and there will be no restriction on the height of road vehicles. In total the bridge will measure 137 metres (150 yards) in length and 18 metres (20 yards) wide. The central span, which will open to marine traffic, will provide a 19-metre (21-yard) navigation channel. The bridge will have two major mechanical items, the main pivot hinges and a pair of hydraulic rams. In order to ensure reliability, the power pack will be duplicated to form a back-up system in the event of failure. A further diesel hydraulic unit may be provided, so that in the event of total loss of the main system the bridge could still be operated at reduced speed.

The Twin Sails vision, although controversial, will change Poole and its waterfront. Will it ruin the nature and charm of the Back Water Channel forever? Or will it create an iconic skyline and enable necessary development?

Proof that the Electric Palace is back in business! The cast of the 2007 pantomime, Cinderella.

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