An Innovative Foundation Saves Millions for Florida Polytechnic University

An official topping-out ceremony in April marked a major milestone in a decade-long venture to create a center of learning dedicated to science, technology, engineering and math (STEM) in the Lakeland, Polk County, region of Florida. From the initial vision of a single university leader in the early 2000s through the eventual design and construction of the first iconic building, KCI has been relied upon as the engineer-of-record for geotechnical design and construction support for the new home of Florida Polytechnic University.

Planning for the 500+ acre campus spans 20 years. In addition to the IST Building, Phase 1 calls for a campus gateway and loop road, parking, and several off-site buildings. Courtesy of Festina Lente, LLP. © 2013 All Rights Reserved
With its graceful feathered steel pergola, soaring columns, and arched commons, the IST building has been referred to as a cathedral of learning.

The $60 million Innovation, Science and Technology (IST) Building, the campus’s first, was designed by international architect Santiago Calatrava and his firm Festina Lente LLP. Featuring a moving shade structure and a future solar array, the oval-shaped building includes 160,000 square feet of classrooms, laboratories, offices, an auditorium and a commons. “Calatrava is both an architect and engineer,” said KCI Vice President Anu Saxena, PE, NAFE. “While his designs are aesthetically pleasing, everything has functionality and purpose.”

The latest addition to the state’s public university system can literally say it was founded on innovation. In general, subsurface conditions in Florida can be challenging, and the selected site exhibited particularly weak or loose subsoils. “Sax [D.S. Saxena] had a whole history of this parcel,” said Florida Poly architect John White. “He had been involved with geotechnical work in the county for many years and knew about the mining activities that had gone on in this area.” KCI’s local knowledge and expertise proved critical when the team acknowledged that a combination of strict settlement criteria and foundation requirements were driving up construction costs.

Florida Polytechnic University Foundation Plan
Instead of deep piles, the foundation design called for a grid of 1,200 stone-injected columns, each 35 feet deep, to support a web of shallow footings under the IST building. Four mega-columns sit atop 40 columns each.

Four mega-columns carry significant loads as part of the IST building’s structural steel inner core. KCI’s comprehensive analysis recommended reducing these loads slightly and changing the structural design of the building to a braced-frame approach that ties the building and settlement together. These adjustments facilitated the use of soil improvements and shallow foundations in lieu of a deep pile foundation system, while relaxing movement parameters and lowering costs. “It allowed us to create a grid system of footings that float on top of the ground under the slab,” said KCI Vice President D.S. “Sax” Saxena, PE, NAFE, FASCE. “Otherwise we would have been driving piles.”

Vibro-replacement is not uncommon in Florida, but the combination of significant loads and mined soils made this site a unique application.

The team selected vibro-replacement, which calls for subsurface injection of pressured stone, as the optimal ground improvement methodology. A total of 1,200 stone-injected columns, 35 feet deep, were required to support the IST and other buildings. Each shallow foundation sits atop at least two columns, while the four large mega-columns are supported by 40 columns each.

KCI recommended a braced-frame approach that ties together the building so that it moves and settles as a unit. Everything is connected as one, enabling settlement criteria to be relaxed and a combination of shallow foundations and soil improvement to significantly reduce construction costs.

Built on a solid foundation, both metaphorically and physically, the campus and first academic building are taking shape. After opening its doors next fall, the school hopes to grow its student population to 16,000 over the next decade and has plans for 600 faculty, administration and staff members.