Paramus Park Mall in Paramus, New Jersey is one of the country’s largest shopping malls. It is shaped as a four-legged zigzag, with an anchor store at each end and the mezzanine-level food court encircling an atrium which features a 30-foot terraced waterfall surrounded by vegetation and punctuated by a pair of escalators.
At the time of a planned expansion in 1999, the two-story structure was experiencing unacceptable foundation and floor slab settlements. Nicholson was contracted to install micropiles through the existing spread footings and grade beams. In addition, voids that were present below the existing floor slabs were grouted to reduce the risk of future movement and structural damage. Nicholson designed the connection to the existing structure by coring and grooving the building foundations. These connection capacities were proved by conducting two pullout tests. A total of 66 piles were drilled to depths averaging 55 feet below the existing slab elevation. The design load of the piles was 176 kips in compression.
Nicholson installed the piles using rotary duplex drilling to seat the 8 5/8-inch casing to the top of bedrock with water as the flushing medium. A 7 3/8-inch roller bit was used to drill the rock sockets. All piles were installed in low headroom conditions using a mini electric drill rig. Obstructions consisting of boulders and wood made drilling conditions difficult.
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