DeWitt-Dunn A.J.V. Installs Sheet Piling Horizontally

Impenetrable bedrock, soil instability and a restrictive work environment were no match for Heath Dawson and his team.

Creative people seek creative solutions. "I've been in the sheet piling business for 25 years," said Mike Jones, territory manager for Hammer & Steel. "This is the first time I've seen sheet piling installed horizontally."

Jones was speaking of a recent Master Facilities Expansion and Renovation project at St. John's Regional Health Center in Springfield, Missouri. The construction manager, DeWitt-Dunn A.J.V. - a joint venture of Springfield-based DeWitt & Associates, Inc. and the Kansas City, Missouri firm of J.E. Dunn Construction Co. - was required, as part of the contract, to build a concrete tunnel that would accommodate electrical conduit, chilled water pipes and steam pipes.

The tunnel posed several construction problems. In addition to very tight site restrictions, there were unstable soil conditions that dictated the need to install shoring for the tunnel excavation.

Unfortunately, a bed of impenetrable limestone, three to four feet below the bottom of the excavation, meant there wasn't enough material to properly toe-in with conventionally driven sheet piling.

DeWitt-Dunn devised a unique and economical solution - placing the sheet piling horizontally. They proposed to sink 14' vertical H-beams, braced with 8" steel pipe spreaders, and to place quadrupled PZ-22 Steel Sheet Piling horizontally between the flanges of the H-beams. The PZ-22 would provide a high section modulus with a low weight per square foot.

"We weren't sure we would be able to hold the banks until the sheeting was installed," recalled Heath Dawson, the project manager "so we asked Hammer & Steel to deliver the sheets in quadruples." That minimized the number of unlocked seams and speeded placement.

"It's commonplace to pair sheets," noted Jones, "but quadruples are unusual." The H-beams were set at predetermined spacing, so all the sheets had to be supplied in the same length - to a close tolerance - and each end had to be cut squarely. The biggest challenge, according to Jones, was in handling because the pieces can slip out of alignment. "The danger points are in loading and unloading the quadruples on the trailer and in laying them in place," he explained. "In the end, everything worked out very well."

Dawson agreed. He particularly appreciated Hammer & Steel's quick response to a request for additional sheets once the project was well underway. "We called and had the extra material within a few days," Dawson said. "Hammer & Steel provided excellent service."

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