Pad foundations

1. Consist of an isolated base under piers or columns.
2. used under point loads such as coluumns , but can be used under ground beams to transfer continuous loads
3. Transfer the loads to a lower level where soil of sufficient loadbearing strats exists
4. Where the subsoil has poor bearing capacity for some depth below the surface , or on made up ground , it is often economic to use iers on pad foundations to support the load of buildings.
5. the piers is function to support the reinforceed concrete ground beams
6. Pits are excavated down to the necessary level , the sides of the excavation temporarily supported and isolated pads of concrete are cast in the bottom of the pits
7. Reinforced concrete piers are cast on the pad foundations up to the underside of the reinforced concrete beams that support walls
8. The piers will be built at the angles , intersection of walls and under the more heabily loaded wall .
9. THe ground beams may be just below or at ground level , the walls being raised off the ground beams
10. THe most economc plan shape is a square , but if the coloumns are close to the site boundary , it may be necessary to use a rectangilar plan shape of equivalent area .
11. THe reaction of the foundation to the load and ground pressures is to cup , and therefore main steel is required in both directions
12. Incorporated in the base will also be the strater bars for a reinforced concrete column