Designing the new Wilkie D. Ferguson Jr. Miami Federal Courthouse presented a unique challenge. The architects had to balance off energy goals versus hurricane requirements and blast-resistance criteria. Architects Guide to Glass & Metal spoke with Tim J. Blair, vice president of Hellmuth, Obata & Kassabaum, Inc. (HOK), who served as project manager for the project on which his firm was associate architect, about these challenges and the role the glass played in the solution.

AGGM: Miami’s building codes are very strict as are the General Services Administration (GSA) guidelines for federal buildings. How did this affect the design of the building and its use of glass?

TJB: It seems that successful design is often the result of competing priorities. The Miami Federal Courthouse, which was designed as a collaborative effort between Arquitectonica (ARQ) and HOK, is no exception. The GSA, in conjunction with the Department of Energy (DOE), imposed stringent energy goals for the new federal courthouses. Based on several runs of the life cycle cost analysis (LCCA), ARQ/HOK had met the BECON goal of 550 MJ/SM, the metric version of energy consumption with KWH/SF (kilowatt-hours/square foot) being the Imperial equivalent, at the end of design development.

As we proceeded into construction documents, further analysis of the 9/16-inch laminated glazing revealed that the actual U-value for the glazing was 1.12, as opposed to the value of 0.69 required to meet our energy goals. The 9/16-inch laminated glazing is required to meet the large missile requirement of the Florida Building Code for hurricane design. ARQ/HOK utilized this glazing throughout the building to maintain a consistent aesthetic appearance. The other challenge was to meet the blast criteria for the project. The 9/16-inch laminated glazing proved to be so strong that it was imposing blast loads exceeding 850 psf on the framing members of the curtainwall system.

AGGM: What was the design solution?

TJB: We utilized laminated-insulating glazing within the small missile zones of the building which met the requirements for hurricane design. The 9/16-inch laminated glazing was required by the Florida Building Code at the lower level atrium lobby, which is shaded from the Florida sun by a perimeter colonnade. However to meet the aesthetic goals, Viracon agreed to provide laminated-insulated glazing within both the large and small missile zones. Also, the laminated-insulating glazing meets the blast criteria and reduces the pressures on the curtainwall framing system.

Although the premium for the laminated-insulating glazing was approximately $650,000, the increased performance of the glazing allowed us to reduce the size of the chillers, pumps and cooling towers which offset the first cost of the glazing. Not only did the Miami Federal Courthouse meet the energy goals, hurricane requirements and blast criteria, but it also exceeded the energy goals and proved to be more energy efficient from a life-cycle cost perspective.

Design Comments
Bernardo Fort-Brescia, co-founder and principal of Arquitectonica, has this to say about the design of the structure.

“Despite—or perhaps because of—the Miami Courthouse’s imposing scale, we wanted to underline the concept of transparency for the process of justice, literally and metaphorically. We wanted lots of natural light inside and extensive views of the ocean and nature in all its beauty.

“Despite the security concerns, we wanted people inside the courthouse to feel more comfortable than people do in U.S. courthouses constructed in previous decades; one thinks of long, claustrophobic, almost guilt-inducing, window-less corridors and barricaded courtrooms. We wanted as much natural light in the building as possible.”

Award Winner
The nonprofit Protecting People First Foundation has given its Safety Award to the U.S. General Services Administration (GSA) for the new Wilkie D. Ferguson Jr. Miami Federal Courthouse, the first in the country designed to be both blast-resistant and to withstand hurricane-force winds. The new building, the largest federal courthouse in the United States at 578,000-square-foot spanning two city blocks, meets Miami’s stringent hurricane codes as well as U.S. government security standards for blast mitigation. The courthouse is part of the GSA’s Design Excellence Program, which commissions designers and artists to improve the design and quality of federal buildings.

“We take very seriously our responsibility to construct government buildings and facilities that provide a safe environment for employees, as well as the public,” said Edwin E. Fielder, Jr., regional administrator of GSA’s Southeast Sunbelt Regional Office.

Glass Facts
Viracon supplied all the structure’s exterior glass, approximately 200,000 square feet, in 18 different configurations ranging from skylights to vertical wall facades featuring Solarscreen low-E insulating laminated glass. The glazing contractor was Antamex.

DuPont Butacite and SentryGlas Plus laminated glass interlayers were used in the laminated glass supplied by fabricator Viracon Inc.

Viracon and Antamex tested the laminated glass and custom structural framing system extensively at a certified test laboratory. For large missile resistance (elevations up to 30 feet) Viracon supplied insulating laminated glass with an enhanced hurricane-resistant interlayer. For elevations above 30 feet requiring small missile resistance, Viracon used the same configuration, except with a polyvinyl butyral (PVB) interlayer in the inboard laminate. Viracon also supplied a variety of laminated glass with various blue PVB interlayers for aesthetic appeal. 

USG
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