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

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

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

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

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.

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

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

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.

A minimum seating pressure of 70 g/cm2 (0.7 t/m2), shall be applied and removed before starting the load test.