Selection of the most suitable and effficient type of foundation for a particular structure is a tricky step in the whole structural design process. A well designed super structure will be a waste of time, money and efforts if due attention is not give to the choice of right type of sub structure. This brief article enlists some the most important deciding factors during the process.
The selection of a particular type of foundation is often based on a number of factors, such as:
1. Adequate depth. The foundation must have an adequate depth to prevent frost damage. For suchfoundations as bridge piers, the depth of the foundation must be sufficient to prevent undermining by scour.
2. Bearing capacity failure. The foundation must be safe against a bearing capacity failure.
3. Settlement. The foundation must not settle to such an extent that it damages the structure.
4. Quality. The foundation must be of adequate quality so that it is not subjected to deterioration, such as from sulfate attack.
5. Adequate strength. The foundation must be designed with sufficient strength that it does not fracture or break apart under the applied superstructure loads. The foundation must also be properly constructed in conformance with the design specifications.
6. Adverse soil changes. The foundation must be able to resist long-term adverse soil changes. An example is expansive soil, which could expand or shrink causing movement of the foundation and damage to the structure.
7. Seismic forces. The foundation must be able to support the structure during an earthquake without excessive settlement or lateral movement.