Rotary-Driven Pipe Pile Solution for a Congested Urban Site
摘要
Manhattan’s Upper East Side in New York City (NYC) is known for highly variable and challenging soil conditions due to a historic network of wetland marshes and creeks that once existed throughout the area. Construction projects in this area have often led to settlement of existing structures, many of which are old, low-rise residential buildings supported on shallow foundations bearing on uncontrolled fill. This case study presents the design, testing, quality control/assurance, and construction of specialty rotary-driven pipe piles for support of an 8-to-9-story building. The rotary-driven pipe pile does not fit neatly into any of the pile types prescribed in the governing 2014 NYC Building Code (NYCBC), and therefore a project-specific approval from the NYC Department of Buildings (DOB) was required. Challenges encountered during the design and construction included ensuring the pile design methodology was consistent with the NYCBC requirements despite the pile not being a NYCBC-prescribed pile type, and developing a suitable and repeatable end-of-installation criteria and quality control/assurance program for production pile installation. Ultimately, a thorough index pile installation and load test program and subsequent successful completion of production pile installation confirmed the rotary-driven pipe pile was a cost-effective solution to providing new building support while limiting soil disturbance and adjacent building impacts on a congested urban site.