Design & Construction of Reinforced Concrete Foundations

1. Foundations are usually made of either mass or reinforced concrete
2. where a structure has olny light loadings , such as a domestic building , it is sufficiet to use a mass concrete foundation
3. Where building is either heavy , or transmit the loadings at a series of points , such as in a framed buildings , it is eneconomic to use mass concrete foundation ..
4. The thickness of a mass concrete foundation for a heavy point load would result in a foundation that is costly and adds unnecessary load to the subsoil
5. Reinforced concrete foundations are generally cheaper and easier to construct than mass concrete foundations but will require a structural engineer to formulate an economic design .
6. The engineer must define the areas in which tension occurs and specify the reinforcement required , as concrete is a material which is weak in tension .
7. Concrete is a mixture of cement , sand , aggregates and water in controlled proportions
8. It is the most suitable material to construct foundation as it is a durable material of edequate strength
9. But concrete is a material which is strong in compression but weak in tension .
10. If its tensile strength is exceeded , cracks will occur and resulting in a weak and unsuitable foundations .
11. One method of providing tensile resistance is to include steel bars as a form of reinforcement in the concrete foundation to resist all the tensile forces induced into the foundation .
12. Steel is amaterial which is readily available and has high tensile strength .