This small project required a small extension in Bishopstown, Cork City to be provided with a piled foundation. On commencement of the initial groundworks, the soils were found to be very poor and required specialist intervention.
A trial hole showed that the original building was constructed on a raft foundation on filled material. But to complete this measure for the extension would result in undermining of the existing building so the consulting engineer deemed piling to be the most appropriate solution. Substruck were appointed to complete the works as we had done similar projects for both the builder and engineer before.
We initially did some ground investigation in the form of dynamic probing. The probes showed poor bearing soils to a depth of 1.5 metres until refusal was met at 2.5m. The probing was also the basis for costings.
The works area was only accessible via a 900mm wide side gate which would not accommodate our grout plant or compressor. However, we were able to place all plant over the boundary wall safely with the P15500 crane on one of the trucks. This allowed us to secure our plant and equipment for the duration of the job.
The consulting engineer required 9 nr micropiles with a SWL of 120kN and a dynamic load test to be performed on one nr of our choice. The piles were installed and the test results were 20% of the minimum settlement allowed.