- Researched surficial and subsurface conditions at proposed exploration and structure locations
- Coordination and oversight of over 150 test borings near energized conductors and equipment
- Increased productivity with a second subcontract driller and up to four test boring teams operating concurrently
- Explorations assessed a variety of subsurface conditions, including karst / limestone bedrock
- Both shallow and deeper bedrock conditions encountered
- Zero lost time safety incidents
Challenge
GZA’s geotechnical engineering professionals supported the design of over 25 miles of electric transmission line upgrades encompassing a wide range of transmission and substation structures and a variety of subsurface conditions.
Solution
GZA completed desktop geologic research to document anticipated conditions and prepare a customized exploration plan; conducted subsurface explorations within substations and ROW consisting of over 150 test borings; completed geotechnical soil and rock lab testing; and completed geotechnical analysis and reporting. GZA compiled readily available USGS surficial and bedrock geological data, aerial photography, and USGS topography prior to mobilizing the field activity. With these preliminary findings, GZA quickly identified potentially problematic conditions such as accessibility concerns, shallow rock, karst / limestone conditions, boulders, wetlands, and active farmland/residential areas. The subsurface exploration began with refining the geotechnical scope for GZA’s team based on frequent and detailed discussions with Client. To optimize field progress, up to four drill rigs were operated simultaneously, with up to five field staff providing coordination, quality control observation and value engineering support. GZA’s engineering analysis culminated in three (3) geotechnical engineering reports providing both shallow and deep foundation design parameters and construction recommendations for the wide range of transmission and substation structures. In addition to evaluating the soils and rock encountered for geotechnical engineering characteristics, we also considered seismic and liquefaction concerns.
Benefit
GZA provided the technical and project management skills to complete this extensive geotechnical engineering project speedily and safely.