Raleigh, Wake County, North Carolina
GTA provided geotechnical and environmental services associated with the redevelopment of two adjacent parcels in downtown Raleigh, previously occupied by two existing single-story converted office buildings and surface parking, into a new 11-story, 273,000-SF office tower. During project planning and design, GTA performed geotechnical services including a subsurface exploration including SPT soil borings, rock coring, air-track drilling, deep foundation design (auger-cast piles), lateral foundation (L-Pile) analysis, and shear wave velocity testing for seismic site classification. Additionally, GTA performed environmental services for the project including a Phase I Environmental Site Assessment (ESA), Phase II ESA soil and groundwater sampling, underground storage tank removal observation, and asbestos and lead-based paint surveys. Also, the site was accepted into the North Carolina Brownfield program, and GTA worked with the project team and NCDEQ to develop a Brownfield Work Plan, and Environmental Management Plan (EMP).
During construction, GTA performed field observations, testing, and sampling in accordance with the EMP to assist the contractor in segregating impacted soils during earthwork and deep foundation construction. GTA assisted the project team in documenting the impacted materials hauled off-site, and performed confirmation sampling of import material delivered to the site, and performed waste characterization sampling for acceptance of the impacted material to an appropriate disposal facility. GTA provided construction observation testing and Special Inspection services during deep foundation construction and provided real-time pile capacity evaluations during construction to help the contractor/owner minimize cost impacts associated with a variable rock profile and thick weathered-rock layer at the site, resulting in significant cost savings to the owner. Construction elements of the office tower include the auger cast-in-place pile foundation system, structural steel framing, concrete slab-on-grade ground level, and elevated slab on metal decking, and masonry brick veneer and glass façade. GTA also performed vibration monitoring and cold-formed steel observations for the new office tower.