Time constraints required the first 100m of the road to be completed with surfacing for the opening of the show homes within three months of starting on site.
Before road construction, the foul sewer diversion was required to be installed. As the excavations were deep (up to 5m), health and safety was a priority. On opening, this section of road attention turned to the remainder of the road.
Before commencing any of the remaining road works, the client had to discharge planning conditions surrounding archaeology on the site. With our team in attendance, the archaeological excavations were better managed to reduce delays in the reinstatement of ground for road construction that followed.
With the new sewer being installed ahead of the road construction, priority was given to health and safety on the deep excavations.
Ahead of the spine road, we diverted approximately 400 linear metres of existing foul sewer running under the proposed building plots, relocating it under the new spine road. Included in the works was the installation of a new foul sewer under the remainder of the spine road to service the future development of the site. A cycle/footway would run adjacent to the spine road with a single footway on the opposite side of the road. Both footways would act as utility corridors.
The culvert installations were subject to environmental approvals to ensure that the excavation areas were free from water voles and other fauna first. We worked closely with the Environment Agency (EA) to obtain the necessary Flood Risk Assessment Permits (FRAPs) before installing over-pumping in advance of culvert construction.
The 2m high x 4m wide pre-cast box culvert units were installed on a sand bed before constructing the headwalls using traditional reinforcement and shuttering methods.
Constraints to the works included:
Hydraulically Bound Material (HBM) was the preferred construction for the road being made up of three layers
of cement bound granular material. Each layer increased in strength to provide a solid bound foundation. Using HBM allows for a thin surface course, in this case, 110mm, and therefore provides for more economical road construction over traditional road design of base, binder and wearing course.
HBM is relatively new to road construction and is mostly laid using a paving machine. However, at the Fairways, the decision to place the materials manually was driven by the material supplier’s outputs. Placing the material by hand proved economically beneficial to the overall project.