Scale effect: The ultimate bearing capacity of saturated soil is independent of plate size, but for cohesive soil it increases with plate size. To reduce the scale effect it is necessary to repeat the plate load test with two or three different sized plates, increase the bearing capacity for the original foundation and average the values obtained.
Effect of time: The plate load test is basically a short duration test. For clayey soils, it does not give final settlement. The load settlement curve is not truly representative.
Interpretation of failure loads: Failure loads are well defined, except for simple shear failure. Errors of personal interpretation may involve other types of failure.
Reaction load: It is not practical to provide a reaction of more than 250 KN and therefore the test on a plate larger than 0.6 m width is difficult.
Water table: The level of water table affects the bearing capacity of sandy soils. If the water table is above the level of the fitting, it must be lowered by pumping before placing the plate. The test should be carried out at the level of the water table if it is within 1 m of the fitting.
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