Abstract:
Veit served as the design-build driven pile contractor for an agricultural processing facility in Grand Forks, North Dakota. Project conditions presented a significant opportunity for cost optimization due to the depth to bearing and the large quantity of piles. Subsurface conditions consist of approximately 130 to 150 feet of low-strength, highly plastic clay underlain by dense glacial till.
Working collaboratively with the geotechnical engineer (Braun Intertec) and pile supplier (Atlas Tube), a parametric cost and constructability analysis was performed to evaluate pile sizes, material properties, and installation methods. Key considerations included pile spacing, cost per unit capacity, steel yield strength, downdrag, delivered pile lengths, splice details, and the contribution of concrete in-fill to axial capacity.
The selected solution utilized closed-end steel pipe piles driven to depths of approximately 170 to 190 feet, with embedment of approximately 40 feet into the glacial till bearing stratum. Pile section properties, including wall thickness and yield strength, were optimized in conjunction with anticipated soil setup in the cohesive profile. Driving system selection, including hammer type and energy, was evaluated to achieve required penetration while maintaining acceptable driving stresses and production rates.
Because the required ultimate geotechnical resistance exceeded the structural capacity of the steel section alone, concrete in-fill was incorporated to develop composite capacity. High-strain dynamic testing (PDA) was performed on concrete-filled piles using multiple diesel hammers to verify ultimate resistance, evaluate driving stresses, and refine installation procedures.
This integrated design-build approach resulted in an optimized foundation system that reduced overall project costs, improved installation efficiency, and provided verified performance through field testing, demonstrating the value of early contractor involvement in deep foundation design.