Deep foundation elements are required when structural loads cannot be supported in shallow soil layers and have to be transferred into a deeper soil stratum well below existing grade, and often into bedrock. Such structural support elements can have a wide range of sizes, from 4 to 12 inches in diameter for Micropiles, 16 to 48 inches for CFA piles, and 16 to 24 inches for Displacement piles. Larger round elements (also called Drilled Shafts or Piers) can range in diameter from 2 feet to exceptionally large sizes of 12 feet or more. Rectangular elements called Load Bearing Elements (LBEs) can be installed to sizes of 10 by 5 feet or more. Large-diameter Drilled Shafts or LBE’s can reach depths in excess of 300 feet and can support vertical loads of up to 20,000 tons when socketed into competent rock.
Deep foundation elements are designed to withstand a wide range of loading conditions, from compression, tension, lateral to dynamic loads, and are typically structurally connected to the superstructure (bridge or building). Available construction techniques and equipment are well-suited to coping with a variety of ground conditions, ranging from very loose cohesive or soft non-cohesive soils to hard rock. Expandable clays, as well as caving sands, gravels, cobbles, and large boulders, can be drilled utilizing state-of-the-art high torque and crowd pressure drilling rigs and employing temporary or permanent steel casing for further support of the borehole. Modern polymers and bentonite support fluids enable a very cost-effective installation when soil conditions are favorable.
Malcolm’s expansive fleet of modern equipment, utilizing the most advanced drilling techniques, ensures that projects can be constructed in highly variable ground conditions.