The Challenge

New structures in the development of Kew’s Children’s Garden needed foundations in close proximity to important protected trees.

An elevated timber walkway around an Oak tree provided a particular challenge for the main contractor. Any impact on the tree and its roots had to be minimised so concrete and traditional piling were ruled out.

Some images reproduced with permission from RBG Kew

The Solution

QuadraPile helical piles were installed along with steelwork to provide foundations for the structure. The relatively small diameter of the piles means the impact on tree roots is minimal.

Both vertical and angled piles were used to take the imposed compression, tension and horizontal forces.

In order to suit the load requirements at each point both 100mm and 64mm diameter piles were used.

The lightweight installation equipment, which is all transportable by hand, means no ground-bearing or tracked rig is needed and there’s no requirement for any piling mat or special access arrangements.

In situ proof testing provides confirmation of pile capacities.

Case study reference: 17239