Needing to expand its library, San Francisco State University (SFSU) first had to have a seismic upgrade of the existing six concrete levels of the J Paul Leonard Library and Sutro Library before the addition of 5 floors of new concrete. Unbuildable for years due to budget and constructability issues, SFSU turned to Barnhart Balfour Beatty to execute a design-build delivery. One of the largest unknowns on the project was the ability to resist seismic events of the structure added in phases over three decades since original construction 55 years ago...
To tackle these issues in a cost effective and aesthetically pleasing way, Barnhart teamed with T.B. Penick as the design-build subcontractor for the overall structure. The team’s first determination was to separate the building’s western expansion from the existing building. This allowed fast-track construction of the new structure and enabled a performance-based upgrade design for the expanded existing facility.
The performance-based structural design allowed the Penick team to consider the full capacity of the existing building’s walls and slabs even though they were not constructed to the standards of the current code. This provided a reduction in new shear wall thickness and a considerable decrease in the extent of new foundations. Additional savings resulted from the use of fiber-reinforced polymer (FRP) strips for collector reinforcement in the concrete diaphragms in lieu of reinforced concrete beams cast below the slabs.
The Penick team developed a strategy to address the design, structural and cost issues, ultimately reaching the $17m budget. This netted a savings from previous design of $4 million and improved the phase 1 move-in date by 6 months.