Photo by Connie Zhou, courtesy of Gilbane Building Co.

The project team also had to take out the existing basement to increase foundation strength in order to support the addition of three 20,000-sq-ft floors to bring the building’s height to 11 stories. The project also features a 9,500-sq-ft penthouse level and a new rooftop terrace. Work included repairing degraded concrete slabs and rebar and using carbon fiber-reinforced polymer (CFRP) wrapping to strengthen 120 micropiles and 110 columns.

Design-assist trade contractors played a critical role in supporting ongoing design as construction got underway. During design of a new mechanical room in Levels A and B of the parking garage, for example, the project team discovered that there was insufficient space to configure the new mechanical equipment on Level B alone.

A redesigned layout created a double-height space, including a mezzanine, within a portion of Level A that provided sufficient clearance to place equipment on both levels while also preserving space originally intended to be used for other functions. This also reduced the amount of concrete cutting and structural reinforcement needed to accommodate the building systems.

Similarly, the original building’s low deck heights limited the type of mechanical equipment that could be installed to maintain the desired ceiling heights. Using BIM, the team skillfully incorporated low-profile, 11-in.-deep fan-powered terminal units into the limited space.

Photo by Connie Zhou, courtesy of Gilbane Building Co.

The resulting office headquarters integrates seamlessly into the existing foundation while completely transforming the interior and exterior elements into a 205,000-sq-ft, high-performance LEED Gold facility. The purchase of energy credits will put LEED Platinum certification within reach.

Outside, the building’s curved stone base evokes the way buses and trains make wider turns, while the glass and metal office tower reference the rhythm of riders gathering at stops. Upon entry, Metro employees and visitors are welcomed by three sculptures inspired by characteristics unique to the nation’s capital, including the region’s vibrant cherry blossoms and coffered ceilings found in traditional transit and civic architecture.

The $140-million project was completed in 34 months with a 1.4 OSHA recordable incident rate and a .07 lost-time accident rate during more than 569,000 worker-hours.