The development included the construction of eight retail/restaurant buildings and a four-story residential building at the site of a former manufacturing facility. Subsurface conditions consisted of existing fill materials underlain in succession by up to 10± feet of buried compressible organic deposits and natural sand and gravel.
Two of Northeast Geotechnical’s principal engineers provided design and construction phase geotechnical engineering services for the project. Design phase responsibilities included coordinating and overseeing extensive subsurface exploration (test borings and test pits), engineering design, and report preparation. Engineering recommendations included ground improvement using rammed aggregate piers for foundation, slab, and pavement support; foundation type and allowable soil bearing capacity; surcharge programs to expedite consolidation of buried organics to limit post construction settlement in proposed pavement areas; use of lightweight grout to fill voids below existing floor slabs required to remain in place per the site’s Activity and Use Limitations (AULs); and use of lightweight structural fill for proposed slab support to reduce stress on and subsequent settlement of buried organic deposits.
Pre-construction phase responsibilities included: working with the project team to develop earthwork construction specifications; reviewing project plans to assess that the geotechnical engineering recommendations were properly interpreted and included; meeting with contractors to review the critical geotechnical aspects of the project; and providing the client with input regarding potential earthwork contractors.
Northeast Geotechnical’s director of field services provided earthwork observation and materials testing services for the project. Construction phase services including observing earthwork and foundation installation operations, logging rammed aggregate pier installation, and performing materials testing were provided. Construction phase responsibilities also included addressing engineering questions from the design and construction teams arising from the complex geotechnical conditions encountered at the site, evaluating the progress of the surcharge program, and providing documentation to the Westborough Building Officials.
