COVER STORY
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BY GIGI WOOD
Ekedal Concrete
17 FEET
UNDER THE SEA: Building a Foundation Below Sea Level
C
alifornia-based Ekedal Concrete takes on jobs others shy away from—the type of projects that require years of experience and sophisticated skills. The company received the Concrete Foundation Association’s 2020 Overall Grand Project of the Year Award for Single Family Homes Over 5,000 Square Feet for just such a project. Ekedal constructed a 9,000-sq.-ft. basement foundation, with the bottom of the slab sitting at -17 ft. below sea level along the bayfront in Newport Beach, Calif. “It's a pretty unique project and it gets very complicated,” says Ryan
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Ekedal, president of Ekedal Concrete. “If you don't know what you're doing, you can be in a world of trouble.” DRILLING THE CAISSONS Ekedal was hired to complete the entire structural concrete package, from planning to steel framing, shoring, de-watering, and building the foundation. Building along the water required advanced shoring and de-watering systems. The crew drilled 109 caissons, which are used for retaining water to allow for the construction of bridges, dams, and similar structures. Each of the caissons was 30 in. in diameter and in all, the
total drilling depth was 6,000 ft. The Bauer BG 15H rotary drilling rig was an Italian model that used a continuous flight auger to drill the caisson and pour the concrete through the auger. The interlocking design provided a faster construction timeframe because it eliminated the need for the casing of holes and lagging. The interlocking caissons were made up of hard and soft piles of slurry and concrete. “One (secant pile) would be full of a slurry, like a two-sack slurry, the one next to it, which would basically butt into that caisson a little bit, would be full concrete,” Ekedal says.
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8/11/21 9:12 AM
