Leading hydraulic jacking specialists Bill Boley Ltd have completed a tricky jacking problem at a new housing development in Highbury, North London.

Many buildings and houses across our capital are within a ‘stone’s throw’ of the London Underground System. Developers seeking to exploit every last square inch of land have to ensure buildings in close proximity to the tunnels can cope with the vibration from trains. The main solution is to place a shock absorbing element between the building and its foundations.

From the outside there is nothing to suggest that the 12 new blocks of flats aren’t built on standard foundations. In fact on closer ‘sub-terranean’ inspection it can be seen they are in fact mounted on a series of large compression springs, designed to minimise the vibration from underground trains operating some forty metres below the foundations. Each of the houses weighs around 500 tonnes and the spring ratings were calculated accordingly. However, as the houses neared completion it was discovered that something had gone awry and the springs were starting to splay sideways.

It was clear that the springs would need replacing, but how do you lift a 500 tonne building without causing damage to the structure or services? Bill Boley Ltd has extensive experience in controlled hydraulic movement and the company was commissioned to carefully lift the buildings off their springs so that new ones could be fitted. 100 tonne hydraulic jacks were placed at each of the spring mounting locations, one block at a time, and then jacking load was slowly applied simultaneously to take the load off the springs. Once this had been achieved the springs were replaced and each building carefully lowered down.