A 4-story school with basement was constructed in a highly developed urban area in the Bronx, New York. The project site was occupied by a series of buildings ranging from 2 to 7 stories high. Multi-level retaining walls along two sides of the property kept the city streets as much as 25 ft above the project site grade. Construction of the school required demolition of several existing buildings and replacement of the existing retaining walls.
Yu & Associates (YU) was retained to perform a geotechnical study. Borings were completed both prior to and after building demolition.
Due to the variable subsurface conditions across the project site, a design combination of footings bearing on soil, decomposed rock and sound rock was recommended. Geotechnical design parameters for the foundation and retaining walls were developed as the latest design criteria seismic considerations meeting the requirements/guidelines established in the NYC Building Code.
During construction, YU provided subgrade inspection services to ensure that subgrade conditions were compatible with the various design bearing pressures.