Tesco Distribution Centre, Severnside, Piling

Simons Construction secured a major award from Tesco to construct a large distribution centre on the outskirts of Bristol.

This fastrack building was designed for a floor load of up to 80kN/m2 on a site underlain by between 7m and 10m of alluvium. In turn these soft soils were underlain by impersistent gravels and hence mudstone. A tight performance criteria was required and thus the only geotechnical solution possible was to support the building on piles.

Given that the site was previously low lying farmland a thickness of some 1m of fill had to be placed on the site which meant the piles had to be designed for negative skin friction. A total of 5948 piles carrying up to 672 Kn were installed using both Driven Cast In Situ and Vibrex piling.

Vibrex driven piles use a high amplitude vibrator mounted at the top of the tube to drive the pile tube to depth. The vibrex system is fast and generates no spoil. In the case of the floor slab 900mm dia enlarged head piles were constructed to a tolerance of +0/-25mm which removed the need for a groundworker cutting down the piles.

This system has been pioneered by Keller particularly for distribution warehouses with large floor areas as any time saving in preparation of pile heads shaves significant time off the programme.