To pile or not to pile?

As in many city centres, the site of the proposed reconstruction of River Plate House in the City of London was crowded with legacy foundation piling. The client wanted to reuse piles where possible but the new building had a different load distribution.

A 3D FEA model was used to compare different foundation options including a raft, raft on existing piles, a raft on cut-down existing piles and pile caps composed of new and old piles.

Highlights

• Back-analysis of pile load tests on under-reamed piles in similar ground conditions to validate the modelling of the existing piles.

• Creation of 3D FEA model of existing basement and foundations with advanced non-linear models for the soil layers.

• Simulation of demolition, basement deepening and reconstruction with different foundation options.

• Output of raft settlement, raft bending moment and party wall settlement with the different foundation options.