Foundations over Piles

Minimising settlement with Load Transfer Platforms

When you have to build embankments over weak foundation soils which are too deep to viably excavate and you can’t afford any significant  settlement  – such as adjacent to sensitive structures – the embankments usually need to be constructed over a deep foundation using piles or vibro concrete columns (VCCs) bearing on firmer strata below. Traditionally, expensive concrete rafts have been used to distribute the load evenly onto the piles – but usually the most economic solution is to construct a Load Transfer Platform (LTP).

How Tensar geogrids and Basetex can help

There are two types of Load Transfer Platform: Enhanced Arch and Tensioned Membrane. An Enhanced Arch Load Transfer Platform has a reinforced granular layer with good quality fill ‘locked’ in place by multiple layers of Tensar geogrids. The Tensioned Membrane Load Transfer Platform is designed so the embankment is supported directly by two orthogonal layers of high strength Tensar Basetex geotextile spanning in catenary between the pile heads, and can use poorer quality fill.

The benefits

Constructing a Tensar Load Transfer Platform on a deep foundation can bring several benefits:

• Avoids the delay required for consolidation settlement
• Reduced costs: compared with expensive concrete rafts or ground beams, an LTP can be cost effective
• Faster construction: both types of LTP system can be rapid and economical to install
• Ground bearing slabs : the Enhanced Arch LTP has been used directly below ground bearing floor slabs to shorten the design span and reduce the requirement in the RC slab from rebar to steel fabric which does not require the time and cost for steelfixers
• A proven, reliable solution: using Tensar’s experience as the specialists in ground stabilisation