Hugh K. Leatherman Sr. Terminal Containment Wall Remediation

After more than 20 years of planning and preparation, the South Carolina Ports Authority (SCPA) completed a new state-of-the-art shipping terminal near Charleston Harbor. The Hugh K. Leatherman Sr. Terminal significantly expanded South Carolina Ports’ capacity with three massive ship berths, a 47-acre container yard and five 169-foot cargo cranes—among the tallest on the East Coast.

Early on during the project, contractors hit a snag. In 2014 construction activities deformed a containment wall founded in the site’s soft clayey soils by as much as three feet laterally. The containment wall needed to be remediated as efficiently as possible to keep construction moving. GeoEngineers got the call.

Our performance-based engineering team got to work on a ground-improvement strategy that would protect the overstressed containment walls. They reviewed historical boring information, construction documents, geologic soil conditions, and ultimately recommended a combination of concrete rigid inclusions, a relieving platform, and battered piles to support the walls. This ground-improvement design streamlined the construction process and reduced costs for the port authority compared to other options. Our team also provided an independent peer review of geotechnical recommendations for fill placement behind the retaining walls.

Approach

• Geotechnical conceptual evaluations for containment wall remediation: A GeoEngineers team carefully compared two options to remediate the deformed containment walls; one using a structural approach and one using a ground improvement program. SCPA ultimately selected the ground improvement option based on GeoEngineers’ analysis.
• Seismic design criteria: GeoEngineers’ seismic specialists collaborated closely with the project team and SCPA to select the most appropriate seismic design criteria for the remediation design.
• Geotechnical design: GeoEngineers analyzed the performance of the containment wall which included long term consolidation, liquefaction susceptibility, and global stability for unimproved and improved conditions both during and after construction.
• Foundation design: The team provided geotechnical recommendations for the structural design of the plumb and battered piles supporting the relieving platform and wall.
• Ground improvement program: GeoEngineers designed a ground improvement program consisting of concrete rigid inclusions and relieving platform behind the containment wall to stabilize the system and prevent further movement.
• Geotechnical peer review for tidelands fill phase: GeoEngineers provided an independent geotechnical perspective on fill soil to be placed behind the containment walls. This included reviewing soil characterization reports, geotechnical specifications and designs. Our team confirmed the geotechnical design assumptions, advised SCPA and the design team, and provided additional project management throughout construction.

Results

The Hugh K. Leatherman Sr. Terminal is a generational upgrade to South Carolina’s shipping capacity and the first new terminal to be completed in the United States since 2009. Its sprawling cargo facilities and towering cranes could only be completed thanks to the hard work of dozens of contractors and consultants, and GeoEngineers is proud to have played a part. Efficient and timely geotechnical analysis, design and peer review from GeoEngineers’ performance-based engineering helped repair and reinforce damaged containment walls and keep this massive $2 billion project on track.