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

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

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

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

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

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

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.

According to Polishin and Tokar (1957), brick masonry will crack due to differential settlement when the unit elongation amount to 0.005.

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