London City Island
London City Island is a new residential development by EcoWorld Ballymore on the north bank of the River Thames overlooking the O2 Arena and adjacent to Canning Town. One of the last buildings to be constructed is a car park and office located above the route of Crossrail. The original foundation design required the loads to be supported beneath the level of the Crossrail tunnels to avoid over-stressing the tunnels. This required the use of expensive and time-consuming permanent casings as slip linings.
ByrneLooby redesigned the foundations to a combination of bored piles and cfa piles. The slip lined casings were designed out by carefully assessing the loads and movements on the underlying Crossrail tunnels and limiting the additional load on the tunnels to the maximum surcharge allowance. One area immediately above the Crossrail tunnels was designed with low density fill to reduce the applied loads.
Close collaboration with the Crossrail engineers ensured that the resulting design was approved by Crossrail, with significant cost and programme savings compared to the original foundation design.