Monumental Engineering at Stonehenge
The iconographic Stonehenge is a World Heritage Siite in the most delicate of environments. London Bridge Associates were called upon to develop a motorway construction plan around this ancient monument to great British engineering.
Client Highways Agency
Skills Design; Project Management
Value Est. £300m
A303 Stonehenge Improvement Scheme
Description: The new Stonehenge Improvement Scheme was to run from the outskirts of Amesbury to west of Winterbourne Stoke along the alignment of the existing A303 road in Wiltshire. The route for the new dual carriageway road was to run near to some residential properties and go into a bored tunnel adjacent to Stonehenge.
Early Contractor Involvement
The project involved the design and construction of a new road to provide an upgraded service along the A303. The procurement approach adopted by the Client made use of Early Contractor Involvement (ECI) to design the scheme, take it through the Public Enquiry Process, issue Draft Orders and ultimately take the scheme into construction after a favourable outcome from the Secretary of State. Unfortunately the Secretary of State decided to shelve the scheme and neither this scheme nor any other scheme has been taken forward.
The scope of works involved the design and construction of some 12kms of new dual carriageway, 2100m of 105m2 twin bored road tunnels, various structures, associated ventilation design, fire life safety, and mechanical and electrical control systems. This would have been the first time the Highways Agency would have adopted this innovative procurement approach for the design and construction of a complex infrastructure scheme involving a tunnel.
London Bridge Associates provided a sub-consultancy role to the Contractor, Balfour Beatty Costain JV for the design and construction of the Stonehenge Tunnels. Our role involved working closely with the JV’s designers for the scheme, reviewing programme, constructability and maintainability issues as well as Whole Life cost and developing the operational functionality using Business Case model approaches.
The team, who also provided support to the BBC JV during the tender, has been involved in the development of the design optioneering, assisting with the preparation of the Environmental Impact Statement and taking the scheme through the Public Inquiry process. Upon a successful outcome and decision by the Secretary of State the team would have had a key role in the construction of the works.
Increased certainty on costs
In addition the contractor was able to bring increased certainty to the projected out turn costs for the delivery of the scheme along with a highly focused approach to operational and maintainability aspects.
Fire Life Safety Design
Through innovative approaches adopted by the Client and the Contractor most of the third party design, construction and operational issues were resolved. Monthly meetings steered by the Tunnel Design and Safety Consultation Group offered a good forum for the discussion and resolution of issues. In particular the Fire Life Safety design and emergency procedures were developed in close cooperation with the Emergency Services to a point where the initial design basis for the scheme was agreed. Likewise the forums offered opportunity for other third party objectors to raise and discuss issues outside the Public Inquiry process and thus ensure the Public Inquiry programme could be maintained.
Mitigating Environmental Impact
Many achievements were made possible with respect to project management and delivery across all disciplines. The design focused on value management and functionality with particular emphasis on the mitigation of environmental impact and the needs of the end users.
The Contractor was able to call upon his design and construction experience to manage the numerous design risks and scheme development issues, which arose up to and during the Public Consultation period.
Through the ECI approach the contractor was able to identify many design and construction risks which otherwise may have gone unrecognised until the construction phase by which time the implications could have had significant consequences for the successful outcome of the scheme.