Plate Bearing Tests For Working Platforms

During piling and other construction works, a working platform is often constructed across the site. These platforms comprise aggregate material placed and compacted to a designed thickness. Satisfactory performance of the platform may be confirmed by a plate bearing test. Current guidance given on plate bearing testing of granular soils suggests that the plate be at least five times the nominal size of the coarsest material. For a working platform this may be large and the reaction load required from plant and resources to carry out the bearing test may become excessively high. The aim of the research presented in this paper was to investigate the effect of particle to plate size ratios to establish if the use of a smaller plate would still allow a reliable test to be performed on site. Plate bearing tests were carried out in a centrifuge using a large, coarse grained limestone. The limestone was graded to a scale representation of 6F2 material, a commonly specified particle size distribution for working platforms. The size of plate was varied and the load displacement response recorded. The measured bearing capacity was correlated with the ratio of particle to plate size.