A major house building scheme to the west of Manchester comprising 148 residential units. The project brief was to provide a cost-effective foundation system, safely and on time. The works are to be split over a number of phases which in total has a value of £963,000. Each phase was designed, approved, and scheduled for manufacture within 4 weeks. The site works consisted of installing pre-cast caps and beams, heave precautions, and were infilled with concrete at a rate of over 200m per week.
Ground conditions varied across the site, some areas requiring ground heave precautions.
The access between areas was via a public road, necessitating careful coordination of deliveries and transport.
Groundwater was present at a high level which meant the piling mat was installed at a higher level than requested. The relatively high level of the main drainage outfall meant a number of beams had to be lowered locally to allow the drains to pass over the top of the beams and still allow for sufficient fall of the gradient.
A total of 4400 metres of pre-cast ground beams over 4 phases. Those complete were installed at a rate of 250m a week. Higher mat levels due to the need to keep the stone out of the water to prevent degrading meant RB had to excavate surplus material and store to the rear of the plots and seal.
Desiccation due to the influence of trees meant some plots were installed with heave precautions to prevent ground movement from damaging the structure. This was achieved by using 100mm thick sheets of polystyrene under the caps and cordek ground form under the beams.
A number of steel piles were installed instead of the designed concrete piles to the north west of the site due to the proximity of existing houses as the vibration of the concrete pile was too high. The correctly sized caps were ordered along with the reinforcing continuation bar and installed without causing any delay to the programme.
The high outfall level of the main drain to be connected to the main road meant some beams that had drainage passing around them had to be checked against the drainage levels to prevent any clashes. Where this was the case these beams were dropped to allow the drains to pass over the top.
Vistry Partnerships’ Managing Director of JVs for the North West, said:
“Not only is the Heath Farm Lane scheme an important project for Vistry Partnerships, but it will play a central role in transforming Trafford’s housing supply so we are delighted to have Roger Bullivant on board to help turn our idea into a reality.”