How do you choose the best deep foundation for your design project?

1 Soil conditions

The first step in selecting the best deep foundation is to conduct a thorough geotechnical investigation of the site. This involves drilling, sampling, and testing the soil to determine its properties, such as strength, stiffness, bearing capacity, settlement, and groundwater level. The soil conditions will affect the design, installation, and performance of the deep foundation. For example, if the soil is very soft or loose, you may need a deeper or larger foundation to avoid excessive settlement or failure. If the soil is very hard or dense, you may need a more powerful or specialized equipment to install the foundation.

2 Load characteristics

The second step in selecting the best deep foundation is to analyze the load characteristics of your structure. This includes the magnitude, direction, and distribution of the loads from the building and the environment. The load characteristics will affect the type, size, and configuration of the deep foundation. For example, if the structure is subjected to large axial loads, you may need a deep foundation that can resist compression, such as piles or drilled shafts. If the structure is subjected to large lateral loads, you may need a deep foundation that can resist bending, such as caissons or micropiles.

3 Foundation types

The third step in selecting the best deep foundation is to compare the different types of deep foundations available and their pros and cons. The most common types of deep foundations are piles, drilled shafts, caissons, and micropiles. Each type has its own advantages and disadvantages depending on the soil conditions, load characteristics, and project requirements. For example, piles are relatively easy and fast to install, but they may not be suitable for very hard or rocky soils. Drilled shafts are very strong and rigid, but they may be expensive and time-consuming to construct. Caissons are very effective for lateral loads, but they may require extensive excavation and dewatering. Micropiles are very versatile and adaptable, but they may have limited load capacity and durability.

4 Cost and time

The fourth step in selecting the best deep foundation is to estimate the cost and time involved in the design, installation, and maintenance of the deep foundation. The cost and time will depend on the type, size, and number of deep foundations, as well as the site conditions, equipment, labor, and quality control. The cost and time will also affect the feasibility and profitability of your project. Therefore, you need to balance the performance and reliability of the deep foundation with the budget and schedule of your project. You may need to consider alternative or innovative solutions that can reduce the cost and time without compromising the safety and quality of the deep foundation.

5 Codes and standards

The fifth step in selecting the best deep foundation is to comply with the relevant codes and standards that govern the design, installation, and testing of the deep foundation. The codes and standards will vary depending on the location, jurisdiction, and type of project. The codes and standards will provide the minimum requirements and guidelines for the selection, design, installation, and testing of the deep foundation. They will also ensure the safety, quality, and performance of the deep foundation. You need to follow the codes and standards that apply to your project and consult with the authorities and experts if you have any questions or doubts.

6 Evaluation and verification

The sixth step in selecting the best deep foundation is to evaluate and verify the performance and behavior of the deep foundation after installation. This involves conducting field tests, such as load tests, integrity tests, and settlement measurements, to check the capacity, quality, and settlement of the deep foundation. The evaluation and verification will confirm the suitability and adequacy of the deep foundation for your project. They will also identify any problems or defects that may affect the performance and durability of the deep foundation. You need to perform the evaluation and verification according to the codes and standards and the design specifications of your project.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?