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 settlement of the plate is measured with the help of sensitive dial gauges. For square plate, two dial gauges are used. The dial gauges are mounted on independently supported datum bar.

The plate load test essentially consists in loading a rigid plate at the foundation level, and determining the corresponding to each load increment.

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 use of reaction truss is more popular now-a-days since this is simple, quick and less clumsy.

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.

The rate of settlement is defined as the slope or the relative settlement between two points divided by the horizontal distance.

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

It is suggested that allowable pressure should be selected such that maximum settlement of any individual foundation is 25 mm.

The bearing plate is either circular or square, made of mild steel of not less than 25 mm in thickness.