PILED FOUNDATIONS AND FOUNDATION UPGRADES

Piled Foundation : Lever Brothers, Warrington

Bottom driven drop hammer piling : Number of foundation piles 24 : Size of piles 327mm dia. piles

Branlows are used to being severely restricted and a recent contract involved the successful installation of piles in a highly environmentally sensitive area!  A solution for upgrading a household detergent production facility at Warrington for Lever Bros included restrictions on access, headroom, noise, vibration levels and fume emissions!  The contract was to supplement the existing piles as the original piled foundations had been significantly downgraded due to sulphate attack over the years.  Twenty four bottom driven piles of 327mm diameter were installed to depths of  12m using our new range of bottom driven drop hammer rigs.  The piles were tested to prove safe working loads of 50 tonnes

Foundation piles

T K MAX, Wakefield

Hybrid of drilled and driven piling system: Number of piles 74 : Size of pile 300 mm dia.

T K Maxx, a nationwide retailer selling famous name fashion and homeware, recently acquired a substantial warehouse facility in Wakefield.  As part of its expansion drive in the UK, it required immediate installation of three mezzanine floors.  Branlows’ contract involved the installation of 74 foundation piles to depths of around 6m with foundation piles under each mezzanine stanchion leg.  Due to the nature of the loose and variable infill material below the existing slab, loads of 50 tonnes per stanchion had to be supported on a new independent piled foundation.  Branlows were responsible for the complete groundworks package, from coring through to making good of the existing slabs in a contract valued at £75,000.  The project involved drilling 450mm diameter holes in the existing concrete slab and installing the foundation piles.  It was imperative to ensure that the piles were completely isolated from the adjacent slab, preventing the transfer of vertical loading to the slab structure.  We used two mobile piling rigs, one utilising specialist drilling techniques with air flush and percussive drills, with the second rig employed to drive the casings to the required set in the pre-grouted rock sockets.  The anullus between the steel casing and the drilled pile bore was infilled with grout to enhance the lateral stability of the upper part of the foundation pile.  The method was effectively a hybrid of the more traditional drilled and driven pile.  The foundation piles were successfully tested at working load and one and half times working load, revealing settlements of 3.57mm and 5.08mm respectively. Upon removal of the load test pile, recovery was almost 100% indicating that the pile movements recorded were due to elastic settlement of the pile section as opposed to any movement at the grout/rock interface.