Science Drive Garage, Duke University's newest parking facility, opened in November 2016. The new garage has seven levels and 2,263 parking spaces available to graduate students, faculty, staff and visitors.

The initial geotechnical evaluation performed by another firm observed residual sand and silt weathered from the underlying rock over weathered rock. In their geotechnical engineering report, they recommended supporting the structure on a deep foundation system using caissons extending up to 45 feet below grade. They also recommended auger cast-in-place (ACIP) piles using 24-inch diameter piles extending up to 44 feet below grade.

Due to foundation costs being 30% higher than budgeted, the Walker Parking Consultants retained SME on behalf of the University to provide a second opinion regarding foundation design to see if a less costly foundation system could be used. SME worked with a local geotechnical consultant, ECS, to perform additional soil borings and pressuremeter testing, and assist with geotechnical analysis. Pressuremeter testing involves inserting a special probe into a borehole, expanding the probe in increments against the sides of the borehole, and measuring the volume change at each incremental pressure change. This allows engineers to better evaluate how soil responds to loads, resulting in more efficient foundation systems.

Based on enhanced pressuremeter testing and rigorous settlement analyses, the deep foundation design was changed to shallow spread footing foundations. Three different bearing pressures were used (as high as 7,000 psf.) to coincide with settlement criteria established by the structural engineer (less than 1 inch for perimeter footings and less than 1½ inches for interior columns, with differential settlement less than half of the total settlement). The analysis used the pressuremeter data and actual individual design column loads.

As a result of SME’s value engineering, the project team was able to reduce the foundation costs by $700,000. The savings were about 20 times the fee for the additional geotechnical evaluation and engineering services — a solid return on investment.

The American Council of Engineering Companies (ACEC) of North Carolina
named the Science Drive Garage as its 2016 Honor Award and People’s Choice Award recipient.