Rectangular Combined Footing

A rectangular combined footing is a type of foundation that is used to support two or more columns. It is called a combined footing because it combines the loads from multiple columns into a single footing. This type of footing is commonly used when the columns are closely spaced or when the soil conditions do not allow for individual footings.

Load Distribution

In a combined footing, the load from each column is distributed to the footing based on the relative stiffness of the supporting soil. The load distribution is influenced by factors such as the column loads, column spacing, footing dimensions, and soil properties. In the case of a rectangular combined footing, the load distribution is such that the footing is designed to carry equal loads from each column.

Equal Loads

The correct answer to the given question is option 'B' - equal loads. This means that in a rectangular combined footing, both the columns carry equal loads. This is because the footing is designed in such a way that the load from each column is distributed evenly across the footing.

Advantages of Equal Loads

There are several advantages of designing a rectangular combined footing to carry equal loads:

1. Uniform Settlement: When the loads are distributed equally, the settlement of the footing is also likely to be uniform. This helps in preventing differential settlement, which can lead to structural damage.

2. Cost Efficiency: Designing a combined footing to carry equal loads allows for a more economical use of materials. The footing can be optimized to minimize the overall dimensions and reduce the amount of concrete and reinforcement required.

3. Simplified Design: When the loads are equal, the design calculations for the footing become simpler and more straightforward. The engineer can focus on designing a single footing that can adequately support the combined loads from the columns.

Conclusion

In summary, a rectangular combined footing is designed to carry equal loads from each column. This design approach ensures uniform settlement, cost efficiency, and simplified design calculations. By distributing the loads evenly, the footing can provide adequate support to all the columns and prevent any structural issues that may arise from unequal loads.