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Helical Piles - a Very Restricted Workspace - and Snakes - OH MY!
Nick Gill, Danbro’s field specialist, stands 6’ 4” tall and weighs in at a dainty 265 pounds. He takes up a lot of space and space was limited in the crawlspace of a home in Irmo, South Carolina with a sagging floor and few options to arrest the settlement.
Jerry Shackelford of Shackelford & Sons Contracting was tasked with finding a solution for this problem by his client, a South Carolina property management firm that had invested in the apartment complex. Some of the buildings appear to be constructed on unconsolidated fill and 204 Riversong Road would be a test case for a common problem at this and other properties.
Jerry Shackelford had done his homework and researched a potential fix. Helical piles, which are segmented piles and come in various lengths and can be installed with portable, hand-held equipment, looked like a viable solution. The next step was to find a supplier who would provide the expertise critical to the project’s success. More important would be the training that would enable Shackelford & Sons to replicate this fix on other similar projects.
A chimney was supported by a 15’ long (6” X 6”) beam, and the beam and floor were sagging under the weight. The work to stabilize the floor and arrest the settlement needed to be done from the crawlspace to avoid disruption to the occupants and avoid ripping up the expensive hardwood floor. Overhead ranged from a high of 48” to a low of 20” and seven helicals needed to be installed under the floor joist and floor.
Seven 3’ lead sections with an 8” 10” helical bearing plate configuration and three additional 3’ extensions were installed 15’ to support the 12.5 kip working load/pile. The severely restrictive overhead required that each pile location be excavated to create enough overhead to create enough clearance for the drive head and accommodate installation. Installation equipment consisted of a power pack situated outside the crawlspace, with 25’ of hydraulic hoses attached to a foot pedal. An extendable reaction bar was snugged up against the foundation wall to resist the 2,500 ft. lbs. of torque required to achieve the 25 kip ultimate capacity requirement.
Gill did not bump his head in the severely limited access, but he did have some concerns. “I don’t know if Jerry and the guys were kidding, but they said that South Carolina is considered to be the Australia of the United States as it relates to venomous snakes and spiders.” “Keep your eyes peeled,” the crew cautioned a nervous Nick. In between frequent glances over his shoulder, Nick Gill and the Shackelford team installed the seven helicals to approximately 15’ in the sand/clay mix in two cramped days. “They were really good, quick learners,” Gill observed of Shackelford’s crew. “I’m confident that they will be able to tackle other similar projects with few issues.”
by Pat Haffert
Danbro Vice President
3700 South 26th Street
Philadelphia, PA 19145
Phone: (215) 271-7700