Strap Footing as a Type of Combined Footing

A strap footing is a type of combined footing used in cases where two columns are close to each other, and their individual footings would overlap. It is also known as a cantilever footing or a connecting footing.

Purpose of Strap Footing

The purpose of a strap footing is to combine two or more footings to distribute the load over a wider area and to balance the uneven settlement of the underlying soil.

Construction of Strap Footing

A strap footing is constructed by connecting two isolated footings with a beam or a strap. The beam or strap is usually made of reinforced concrete and is designed to resist bending and shear forces.

Design of Strap Footing

The design of a strap footing involves calculating the loads on the two columns, determining the size and depth of the individual footings, and designing the strap or beam to distribute the load evenly between the two footings.

Advantages of Strap Footing

The advantages of using a strap footing include:

1. Reduced construction cost and time

2. Reduced risk of differential settlement

3. Ability to support heavy loads

4. Increased stability and strength

Disadvantages of Strap Footing

The disadvantages of using a strap footing include:

1. Limited application in cases where the columns are not close together

2. Increased complexity in design and construction

Conclusion

In conclusion, a strap footing is a type of combined footing used to support two or more columns that are close together. It is designed to distribute the load over a wider area and to balance the uneven settlement of the underlying soil. Although it has some limitations, it is a useful and cost-effective solution in many cases.