Fred Fountain, Testing and Analysis Tony Suckling, Balfour Beatty Ground Engineering. This paper was first published in GE’s November 2012 issue.
There have been several instances on construction sites of piling rigs and cranes of various types toppling over while operating on un-bound or weakly-cemented working platforms.
The current method of designing piling platforms in the UK identifies that the key problem is “punching failure”, but relies heavily on modelling assumptions and on site investigation data. In order to certify working platforms at present a few plate load bearing tests are carried out, and unless there are visible problems the test results are usually accepted without question. As a result, just about any platform passes. The relationship between the data from such testing and the design assumptions is uncertain. The method is also slow and laborious and ties up heavy plant so it is unsustainable to carry out many tests across a platform.