Empirical estimation approach & DeepFND Software
1. The Role of Installation Torque in Helical Pile Foundations
Installation torque refers to the rotational force applied to a helical pile during its installation into the ground. Monitoring this torque is essential because it directly relates to the ultimate geotechnical capacity of the pile. Exceeding the torsional capacity of the pile can lead to structural damage, compromising the foundation's integrity. Therefore, understanding and controlling the installation torque is critical for the successful implementation of helical piles.
2. Empirical Approach to Calculate Ultimate Geotechnical Capacity
The empirical approach links the installation torque to the ultimate geotechnical capacity of the helical pile through a torque factor, Kt. This factor varies depending on soil conditions, pile diameter, and other factors. In practical terms, the ultimate geotechnical capacity can be estimated by dividing the measured installation torque by the Kt factor. This relationship provides a straightforward way to estimate the load-bearing capacity of the pile during installation.
Figure 1: Installation torque and geotechnical capacity for various nodes along a helical pile - DeepFND
3. Implementation in DeepFND Software
DeepFND, a deep foundations design software, incorporates this empirical approach to facilitate the design and evaluation of helical piles. The software includes predefined Kt profiles, such as the AC358, which covers piles up to 3.5 inches in diameter, and another profile for larger piles up to 8 inches in diameter. These profiles account for different pile diameters and allow users to edit or add their own profiles based on specific project requirements.
DeepFND performs detailed calculations along the pile depth, taking into account side friction and helical plate bearing capacities at various nodes. For each node, the software calculates the installation torque by dividing the ultimate geotechnical capacity by the corresponding Kt factor for the model pile diameter. This process ensures that the estimated installation torque is accurate and reflective of real-world conditions.
Figure 2: The AC358-2007 installation torque profile as implemented in DeepFND software
4. Graphical Representation and Safety Checks
One of the key features of DeepFND is its ability to present the calculated installation torque values graphically along the pile depth. This graph includes the pile torsional capacity limit, providing a clear visual representation for engineers. By comparing the estimated installation torque with the torsional capacity limit, users can easily determine if the installation process is within safe limits. If the installation torque exceeds the pile’s torsional capacity, the software suggests using larger piles or adding more/bigger helical plates to limit the required pile depth and ensure safety.
Figure 3: Installation torque graph (blue line) and torsional pile capacity (pink line) in DeepFND
5. Ensuring Safe and Efficient Installation
The integration of the empirical approach in DeepFND software enables engineers to design helical pile foundations with confidence. By providing accurate torque estimations and clear visual aids, the software helps prevent over-torquing and potential pile damage. This ensures that the installation process remains within safe parameters, ultimately leading to more reliable and efficient foundation systems.
6. Conclusion
DeepFND software leverages the empirical relationship between installation torque and ultimate geotechnical capacity to provide a robust tool for designing and evaluating helical pile foundations. By incorporating predefined Kt profiles and offering customizable options, DeepFND ensures that engineers have the flexibility to adapt to various project needs. The graphical representation of torque values against the torsional capacity limit further enhances the software's utility, promoting safe and efficient installation practices. With DeepFND, engineers can confidently manage installation torque to achieve optimal foundation performance.
Book A free web presentation:
