I-485 Widening and Bridge Construction (R-4902)

S&ME teamed with STV, Inc. to provide geotechnical investigation, geotechnical design, pavement design, and construction support for the I‑485 Design-Build road widening from East of I-77 to Rea Road in Mecklenburg County, North Carolina. The project spans approximately 9.2 miles and includes the addition of a thru lane in each direction along with auxiliary lanes in several locations.  Six dual bridges along the interstate were widened, four of which crossed water. A new flyover bridge/ramp structure and a new bridge over I-485 were constructed along with four noise walls and three retaining walls.

S&ME provided field services including geotechnical drilling, rock coring, Ground Penetrating Radar surveys along approximately 7 lane-miles on Johnston Road, high-strain dynamic pile testing with a Pile Driving Analyzer (PDA) at each bridge, Crosshole Sonic Logging (CSL) at each interior bent, and subgrade stabilization design/testing along approximately 30 lane-miles.  In conjunction with CSL testing, S&ME also performed concrete coring to investigate anomalies identified in the CSL testing of several drilled piers.  When defects were encountered, S&ME performed additional analysis and consulted with project team to determine an appropriate remediation plan.  S&ME also performed laboratory testing at our AASHTO accredited laboratory.  Engineering analysis and reporting was performed for each structure and specific roadway areas in accordance with NCDOT specifications and design standards. The subsurface investigation reports and foundation recommendation reports were reviewed and approved by NCDOT.  S&ME’s services continued during construction by providing geotechnical support for foundation construction and testing, and embankment construction.