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Case Studies Helical Piles Support Interior Columns

The Gibson guitar building got a makeover when FedEx decided to move its main offices to downtown Memphis. Ram Jack of
Tennessee worked with Burr & Cole Engineering to create a custom solution to see the project to its best completion.

When FedEx purchased a building in downtown Memphis, they soon realized their renovations would need extra help. The old Gibson
guitar building was to be made into main offices for FedEx. The renovations included the addition of a new 2nd floor mezzanine on
the interior of portions of the building. The new foundations to support the new mezzanine columns load would require a strong
foundation to prevent settlement. Burr & Cole Engineering provided a foundation plan that required pile loads of 80 kips allowable
with a minimum safety factor of 2.4 (192 kip ultimate capacity).

After FedEx presented the problem, Ram Jack Tennessee worked with Fortified Engineering Solutions to design the piles. In order to
meet the pile load requirements, 6.625-inch piles were designed with a triple 12"/14"/16" helix configuration and installed with a
minimum installation torque of 44,000 ft-lbs. In order to prevent elastic shortening of the steel pile under load, the inside of the piles
would be fully grouted after they were installed. To verify the pile design, two full scale pile load tests were performed on-site.

After the test piles passed with flying colors,
installation of the piles on the first phase of the
project began. The first phase consisted of installing
and grouting (37) helical piles. The pile installation
on the first phase took 8 days to complete. After
approximately a month of waiting, the footing was
ready for the second phase of piles. Twelve helicals
were installed and grouted in three days. A total of
(49) 6.625-inch grouted helical piles were installed
on the project to an average embedment depth of
36-feet. Everyone was happy with both the quality
of the work and the speed with which the job was
performed. FedEx employees now have a newly
renovated office building with a secure foundation.

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