BIDDERS FOR London's $700M privately financed Thames Gateway Bridge face tight restrictions on design changes because of planning constraints. One of two indicative designs produced by consultant Halcrow will have to be adopted and developed by the successful bidder because there is no parliamentary time for a hybrid bill for the crossing which allow some flexibility to modify designs. Normal highways powers process will be used which means submitting designs for planning approval. A public inquiry will also be needed, pushing the expected start of work to 2009. The crossing is expected to open in 2013.
Halcrow originally produced four options for the new bridge, which will be constrained by the need to maintain shipping access below without affecting flight paths to nearby City Airport. It has since narrowed options to two - a triple arch structure and a concrete box girder structure.
Plans for a rail tunnel under the Strait of Gibraltar, linking Morocco and Spain, have taken a step forward with the agreement last month that a $32M geological investigation should be carried out.
The 38.4km long twin bore tunnel would be excavated between Punta Paloma on the south west coast of Spain near Tarifa, and Punta Malabata, near Tangier in Morocco.
It would lie between 100m and 300m beneath the sea bed, which is 300m below sea level.
A shorter 19km long tunnel could be achieved further east, but would involve construction under a 900m depth of water.
Construction cost is expected to exceed $3bn.
A decision on whether to go ahead with the project will be taken in 2008.