Sea Change Sussex
Breheny Civil Engineering
The North Bexhill Access Road is the latest and final piece in a regional infrastructure improvement programme. A 2.4-kilometre road scheme connecting the new Bexhill- Hastings Link Road (BHLR) in the east with the A269 in the north, the project is one of 12 strategic growth corridors identified under the Strategic Economic Plan (SEP).
CampbellReith was appointed to provide full highway design, drainage design, ground conditions assessment and environmental impact assessment services.
Allen Dadswell administered the construction contract and provided cost planning services, including setting the budget to obtain LEP funding along with subsequent monitoring and control of costs. This element of the project included tendering and letting the contract.
Working collaboratively alongside the appointed contractors, CampbellReith and Allen Dadswell provided overall Project Management and Site Supervision services throughout the project and implemented numerous value engineering/design changes to ensure the project remained on budget.
Our highway design services for the whole route included a full 7.3-metre wide carriageway, a segregated footway/cycleway, three roundabouts, three stopping up orders, four culvert crossings (including two oversized culverts) and two Pegasus crossings. We designed a full SuDS scheme to ensure that the run-off from the new highway met both Environment Agency and LLFA requirements for quantity and quality of discharge.
“In order for the main contractor to begin works on site, CampbellReith identified key risks in the form of a constraints plan to highlight significant issues that could impact on programme. This included controlled two-stage, ecological clearance work within the specified seasons as well as early liaison with key utility providers and the project archaeologists. CampbellReith also procured and managed a targeted Ground Investigation.
One of the main challenges with respect to ground conditions was to provide a cost-effective means of crossing a main river (as designated by the Environment Agency), which has peaty alluvium to 8 metres bgl. Initially, and as part of the original planning application, a 50-metre span bridge was approved to overcome the less than favourable ground conditions.
As part of the on-going cost planning and budget monitoring, it was advised that a new cost-effective solution was required to cross the main river. CampbellReith produced a revised design for a large, oversized culvert on reinforced foundations. We designed a combined system of geosynthetics for both foundation, reinforcement and drainage supported by controlled modulus columns, which provided an innovative and cost-effective solution to this problem. Through this process we demonstrated that it is possible and achievable to design and install reinforced soil using marginal, poorly drained fills, without the need to improve the characteristics of the fill using cement/lime or to import granular material which has both cost and environmental implications.
This sustainable system also encourages rapid vegetation on the slope ensuring a permanently stable structure. This was completed in a timely manner to avoid any unnecessary programme delays.