Factors to Consider in Foundation Design

Any building has two essential parts. The two major categories of buildings are the substructure and superstructure. These two structures are separated by a line called a plinth. The sub-structure is the part below the ground level. The superstructure is the part of the building above the ground level. The structural foundation is the part of the building which is in direct contact with the ground.

Foundation design is the process of designing a construction plan for a building foundation. The strength and stability of any structure depend on its foundation. It is a highly specialized job that is usually performed by a structural or foundation engineer. The foundation is the structural base that stands on the ground and supports the entire structure. So, the foundation design in construction must involve intensive study of the environment and design and materials to be used in the foundation. A strong foundation is necessary for any structure. Many times, the failure of the foundation is responsible for the collapse/failure of the building.

Importance of Strong Building Foundation

• Supports a load of the whole building
• For the overall safety and stability during natural calamities. i.e., earthquakes, floods, strong winds & more.
• It distributes the load from the superstructure to soil uniformly.
• Uniform transmission of load helps in avoiding unequal settlement of the structure.
• It helps maintain a proper level surface to the structure.

A good design must not only be safe but must also save construction cost, time & elements. Let’s have a look at the procedure of designing a foundation.

1. Identify the location of columns, foundation and types of loads that would act on it (For instance, Dead load, Imposed Load, Live load, Wind load): The position of columns and load bearings should be placed on the structure plan. It must give appropriate partial safety factors for these loads. 
2. Determine maximum bearing pressure of the soil using ground investigation report: The study of the site ground investigation helps identify the strength of the soil at different depths. It also helps determine the allowable bearing capacity at various levels.
3. Check on foundation depth: The depth of any foundation depends on several factors such as soil bearing capacity, soil type, frost type, groundwater table and more. The invert level of the foundation is known by the minimum depth below ground level. It can be as low as 450 mm depending on the site and can exceed 1m.
4. Examine the foundation area: The foundation area is analyzed from the working load features and estimated allowable pressure. It helps identify the preliminary design of the type or combined types of foundation to be used. The economics, speed & buildability of construction are responsible for the selection process.
5. Settlement calculations: Calculate the settlement to check that the overall and differential settlements are acceptable. In case if these are unacceptable, then a revised allowable bearing pressure should be identified.
6. Cost control: It is necessary to know the cost before finalizing the foundation type. It will enable you to identify the economics of increasing superstructure costs to lessen foundation costs.

Conclusion

Choosing the right foundation is essential in civil engineering projects. So, it is crucial to be precise with its construction. It would prove best to hire an experienced civil & structural engineering services provider to identify foundation design for your construction project. They can help you decide the right option depending on your project’s size, location, soil type and geographical conditions.