The new $275 million headquarters for the U.S. Department of Transportation (DOT) currently under construction in Washington D.C., is not your average federal building. Spanning two city blocks, the design features a nine-story western tower and an eight-story eastern tower and is designed to withstand forces that buildings in the past were never designed for. Scheduled to open in 2006, the highly secured complex - buildings are set back 50 feet from the street - will house the agency’s more than 5,000 employees.
Opportunities and Challenges
Building a highly secured 1.35 million-square-foot Class-A commercial office complex presented both opportunities and challenges. High tolerance construction methods were required for the 50-year construction system. According to Jason McMannis, project manager for Cleveland Construction, “A 50-year construction system is designed to last twice as long as the standard 25-year system. It utilizes only the best materials as well as advanced engineering methods to ensure the building can withstand time.”
When it came to firestopping the buildings, one of the major challenges was accommodating a 1-inch deflection at some locations with the 50-year construction system. “Potential high movement rates are always a challenge,” said McMannis. “However, we use STI’s SpeedFlex™ joint profile and it has worked really well. We are very happy with the system and are using it in flat floor slab applications throughout the complex.”
Meets Deflection Requirement
SpeedFlex is a high-temperature fibrous joint forming material for use in top of wall construction joints. It is sprayed with an elastomeric firestop overcoating. Because it allows for up to 100 percent compression and extension in joint movement, it meets the 1-inch deflection requirement. According Jeff Wexler, STI regional manager, “The SpeefFlex joint profile allows joint seals to be installed over the joint rather than within it, providing maximum dynamic movement capabilities. It is simply tacked into place and sprayed over, reducing install times significantly.”
Installs Quickly
SpeedFlex replaces the typical mineral wool backing material that has to be stuffed into place. “An installation of mineral wool in this particular application would have been labor-intensive and time-consuming,” explains Wexler. “SpeedFlex was installed in a much quicker timeframe, resulting in significant savings.” According to McMannis, using SpeedFlex and spray resulted in a “35 percent time-saving installation over traditional applications.” He continues, “The spray material goes on smoothly and evenly and, therefore, uses approximately 25 percent less material.” The net result was an install that took less time, looked cleaner, and used less spray material.
