Currently being designed by an Arup-Jacobs joint venture, Arup main crossing manager Naeem Hussain said: "It will be a three-tower cable stayed bridge with spans in the region of 650m. We are now studying different forms of towers and types of deck."
Land searches, environmental surveys and ground investigations for the crossing also got under way this month. The results from these investigations will be used to inform decisions on the design and alignment of the bridge and the connecting road network.
A competitive tendering process for the provision of specialist ground investigation and marine investigation services is currently underway. Transport Scotland expects to confirm the appointment of contractors imminently to allow investigations to begin in the spring.
The existing Forth Road Bridge faces an uncertain future after extensive corrosion was discovered in its cables in 2004. Repairs will cause major traffic disruption to the 66,000 vehicles that use the bridge to cross the Firth of Forth every day.
It was announced in December that a cable stayed bridge would be built to replace the existing Forth Road Bridge and would be designed by the Arup-Jacobs team, which also includes consultant Flint & Neill, architect Dissing & Weitling and cost consultant EC Harris
-NCE's Scottish Transport conference takes place at the Radisson SAS in Glasgow on 18 March 2008.