What Does Combined Footing Mean in Construction

A combined footing is a type of footing that supports two or more columns and is used when the columns are close to each other.

 It is a continuous rectangular footing that spreads the load of the columns over a larger area, providing greater stability.

 The combined footing is typically wider and longer than individual footings and has a greater bearing capacity. It is a type of foundation that is a single large footing that supports two or more columns or walls that are close together. This type of footing is ideal for structures with columns that are closely spaced and have different loads and sizes.

Advantages of Combined Footing

  1. Increased Bearing Capacity: Combined footings have a greater bearing capacity compared to individual footings. This is because the load of the columns is spread over a larger area, reducing the pressure on the soil below.
  2. Reduced Costs: By using combined footings, the number of individual footings required for a construction project is reduced, resulting in lower costs for the project.
  3. Increased Stability: Combined footings provide greater stability to the building compared to individual footings. This is because the load is spread over a larger area, reducing the pressure on the soil below.
  4. Reduced excavation: The excavation required for combined footings is generally less compared to individual footings, as the excavation required for combined footings is typically wider and longer than for individual footings.
  5. Improved appearance: Combined footing provides a clean, neat appearance to the structure, as it eliminates the need for multiple footings and eliminates the space between them.

Disadvantages of Combined Footing

The following are some of the drawbacks of using combined footing:

  1. Increased complexity:  Combined footing is more complex to design and construct compared to other types of footings, as it involves multiple columns and loads that must be considered and calculated.
  2. Increased cost: Combined footing is more expensive compared to other types of footings, as it requires more concrete and reinforcement. This increased cost may not be offset by the reduced excavation, making combined footing less cost-effective for some projects.
  3. Limited applicability: Combined footing is only applicable for structures with closely spaced columns that have different loads and sizes. It is not suitable for structures with columns that are widely spaced or have similar loads and sizes.

Applications of Combined Footing

  1. Buildings with Multiple Columns: Combined footings are typically used in buildings with multiple columns that are close to each other. This is because they provide greater stability and reduce the number of individual footings required.
  2. Bridges: Combined footings are also used in bridges, particularly in bridge piers. They provide greater stability to the bridge and reduce the number of individual footings required.
  3. Industrial Structures: Combined footings are also used in industrial structures, such as factories and warehouses, where multiple columns are required to support heavy loads.

Design of Combined Footing

The design of combined footing involves several factors, including the load on the columns, the soil type, and the depth of the footing. The load on the columns is determined by the weight of the building and the number of floors.

The soil type is determined by a soil test, which is used to determine the bearing capacity of the soil. The depth of the footing is determined by the load on the columns and the soil type.

Conclusion

Combined footing is a type of footing that is used in construction projects to support two or more columns. It provides greater stability, reduces costs, and has a greater bearing capacity compared to individual footings.

Combined footings are used in buildings with multiple columns, bridges, and industrial structures. The design of combined footings involves several factors, including the load on the columns, the soil type, and the depth of the footing.

FAQs

What is the difference between combined footing and individual footing?

Combined footings support two or more columns, while individual footings support one column. Combined footings have a greater bearing capacity and provide greater stability, while individual footings have a limited bearing capacity and provide less stability.

What is the purpose of combined footing in construction?

The purpose of combined footing in construction is to support two or more columns and provide greater stability to the building. It reduces the number of individual footings required and has a greater bearing capacity compared to individual footings.

 

Can combined footings be used in bridges?

Yes, combined footings can be used in bridges, particularly in bridge piers. They provide greater stability to the bridge and reduce the number of individual footings required.

How is the load on the columns determined in combined footing design?

The load on the columns in combined footing design is determined by the weight of the building and the number of floors. This information is used to calculate the load that the columns need to support.

What factors are considered in the design of combined footings?

The design of combined footings involves several factors, including the load on the columns, the soil type, and the depth of the footing.

The soil type is determined by a soil test, which is used to determine the bearing capacity of the soil. The depth of the footing is determined by the load on the columns and the soil type.

What is the main advantage of combined footing?

The main advantage of combined footing is its increased stability, as it is a single large footing that supports two or more columns, spreading the load evenly and reducing stress on any one column.

Why is combined footing more expensive than other types of footings?

Combined footing is more expensive than other types of footings because it requires more concrete and reinforcement, as well as more complex design and construction.

Is combined footing suitable for structures with widely spaced columns?

No, combined footing is not suitable for structures with widely spaced columns, as it is only applicable for structures with closely spaced columns that have different loads and sizes.

Conclusion

Combined footing is a type of foundation used in the construction of buildings and structures, providing increased stability and improved appearance.

However, it also has some disadvantages, such as increased complexity, increased cost, and limited applicability.

By understanding the advantages and disadvantages of combined footing, you can make an informed decision about the best type of footing for your project.

Whether you choose combined footing or another type of footing, it is important to work with a qualified engineer to ensure the foundation of your structure is safe, secure, and long-lasting.

 

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