STRAP FOOTINGS ARE ECONOMICAL THAN COMBINED FOOTINGS WHEN THE DISTANCE BETWEEN THE COLUMNS IS LARGE.

STRAP FOOTINGS :-- Strap footings are provided when an independent footing can not be extended in the adjoining boundary .Strap beams are provided to connect two isolated footings provided under two columns or to connect a footing and a wall .It is assumed that the load is transferred to the soil through the footings only and the strap beam does not transfer any pressure to soil .The areas of two footings are so chosen that the pressure on the footings is uniform and the resultant pressure is in the same line as the resultant loads .The footings are designed as the isolated footings for BM and punching.In case the strap beam is extended beyond the column rib beam , the footing is designed as a Cantilever extended from the rib .In the design of strap beam it is assumed that it does not take any pressure from soil and thus it is so constructed that it does not bear directly on the soil .Further it is assumed that the strap beam is rigid and transfer reactions to the footing , therefore the strap beam is to be designed for SF and BM .This type of footing is economical than combined footing when the distance between the columns is large .