Homebond identify foundations as ‘the most important structural element of any building and great care should be taken to ensure that they are constructed properly.’ Design and construction of foundations must be completed by competent persons and supervised accordingly.
Superstructure cracking is caused by a variety of different reasons but rarely as a result of foundation movement. The measure sought to address this cracking on a commercial property in Kilkenny City by one engineering professional was the installation of a movement joint!!!
However, most proprietary joints only allow for movement of ±3mm as the building expands and contracts over time. If the building exceeds this movement, then there is a more serious problem.
As cracking continued to deteriorate beyond the scope of a movement joint, the Client became more concerned and a second opinion was sought. Crack monitors were installed and confirmed that movement was progressive in one direction.
Substruck Ltd. was employed to complete further investigation in the form of trial holes and ground investigation. Trial holes revealed poorly formed foundations on non-engineered fill material. Dynamic probing and sampling identified the presence of boulders in poorly consolidated fill material to a depth of 3 metres. Probing to further depths was completed for micropile design.
It was now clear that the building was moving due to poorly designed and constructed foundations and underpinning works was required. This was specified as a series of 12 nr micropile supported straddle and cantilever ground beams beneath foundations along the area of distress.