Hybrid Raft-Strip Foundation System for Construction on Weak Load-Bearing Ground

The company sought to develop a novel and structurally stable foundation solution for use on weakened load bearing soil. The solution itself was a hybrid between two existing foundation concepts; raft and strip foundations, as the company determined that existing foundation solutions were not feasible. For example, a traditional strip foundation would be around 600mm wide and 1m deep. This wouldn’t have worked as the foundation was required to sit on unstable ground and would not have sufficiently supported the building. Piled foundations were another potential solution, and this solution was deemed inviable for similar reasons; being that piled foundations would rely on the unstable ground for stability. 

Finally a standard raft foundation solution was considered, which was also inviable due to the loadings imparted by the specified structure. The hybrid foundation subsequently developed was a 2m wide strip foundation, utilising the load bearing capacity of a strip foundation as well as the load distribution capability of raft foundations. As an untested and new application of foundation design, it was important for the company to follow proper procedure and to fully test the product alongside calculations to ensure that the technology functioned properly. To the company’s knowledge, this blend of foundation types had never been attempted and therefore the development of a low penetration strip foundation solution was entirely novel for the industry and provides adequate precedent for undertaking large construction projects on poor ground conditions where there were limited cost efficient solutions available on the market.