Case Studies New-Construction Helicals Support: 70-Foot Cylindrical Storage Tower

Millington, TN

Ram Jack customer, nexAir, needed to install a new tank in their Millington location. The tank was projected to tower at 70 feet. To successfully install the new tank, the company would need to commission the help of engineers to design a solid foundation. All cylindrical storage tanks require a very specific foundation. It is required that vertical, lateral, and overturning moment forces are addressed in the design.

PROBLEM

After being tasked with designing the foundation for nexAir’s new tank, the Ram Jack Tennessee team, partnered with S. Gordin Structural Design, quickly saw that the installation would call for helical piles. Due to the height of the tank, wind would induce a significant overturning moment, which Ram Jack would need to take into account. After calculating all of the loads and reactions, the team of experts began designing the optimum foundation to meet all of the load requirements.

PROPOSED SOLUTION

Once they designed the foundation, Ram Jack, headed by Keith Lusk, along with S. Gordin Structural Design, proposed the installation of (20) 5 1⁄2" piles to be placed around the perimeter edge of the foundation. Doing this would be to resist additional tension and compression loads induced by the overturning moment. (16) 2 7 ⁄8” piles were installed to resist the remainder of the vertical compression loads, providing uncompromised support across the board. The load requirements for the 5 1⁄2" dia. piles called for 71.4 kips allowable, and 48.8 kips tension. The 2 7 ⁄8" dia. piles were installed to 32.3 kips allowable. All piles were installed to an average depth of 50-feet.

OUTCOME

The team managed to install a total of 36 piles and carry the project from start to finish in just four days. Everything went according to plan, and no unexpected hurdles were documented. nexAir was very pleased with the result and the team’s commitment to completing the job within the requested time frame. The remaining tank installation process went smooth and error-free, with a solid foundation to support the tank.

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