The bearing plate used varies in size from 300 to 750 mm with a chequered or grooved bottom.

For simple spread footing on clayey soils, the allowable pressure should be such that the differential settlement does not exceed 1/300.

According to National Building Code of India (SP: 7-1970) the differential settlement shall be kept within limits to which the super-structure can accommodate itself without the distortion, by suitably designing the foundation.

Plate load test is a field test to determine the ultimate bearing capacity of the soil, and the probable settlement under a given loading.

The effect of settlement upon the structure depends on its magnitude, the length of the time over which it takes place, its magnitude and the nature of the structure itself.

Indian standards (IS: 1888: 1982) recommend that the loading of the plate should invariably be borne either by gravity loading platform or by the reaction truss.

The analytical methods for the determination of bearing capacity of footings are based essentially on shear failure.

The loading to the test plate may be applied with the help of a hydraulic jack. The reaction of the hydraulic jack may be borne by either any of gravity loading methodor reaction truss method.

For clayey and silty soils and for loose medium dense sandy soils with N < 15, a 450 mm square plate or concrete block shall be used.

The allowable maximum settlement for warehouse type of structure is 50 mm.