Federal Building Gets More Than a Facelift
GEORGE THOMAS “MICKEY” LELAND FOB
Location: Houston, TX
Owner: General Services Administration (GSA)
Size: 375,000 SF, 22 Stories
Expertise: Structural, Civil, Traffic, & Diagnostics Engineering; Parking; Secure Design
Certification: LEED Platinum Certification
DIFFERENT TIMES, DIFFERENT GOALS
When the George Thomas “Mickey” Leland Federal Office Building (FOB) opened in downtown Houston in 1983 as a privately developed office building, the city’s building code was already 13 years old. Today’s codes are far more stringent. Furthermore, the General Services Administration (GSA), the federal government’s landlord and now owner of the building, has its own new standards.
The GSA’s revisions were in response to the Oklahoma City bombing that brought down the Alfred P. Murrah FOB in 1995, killing 168 people. One study, soon after the bombing, indicated that had the building been designed using today’s seismic building standards, some 50-80% of the structural damage would have been prevented. Among the new federal guidelines: hardened building exteriors to resist blasts; glazing systems that reduce flying glass shards; and structural engineering to mitigate progressive collapse.
GSA’s goal is not complicated: in an age of global terrorism and uncertainty improve the physical security of its buildings and, thereby, the safety of its employees and the public.
Similarly, the GSA has become increasingly concerned about its environmental footprint. In 2011 it set ambitious new goals for improving the environmental, social, and economic impact of its real estate via sustainable design, construction, and life-cycle costs. This includes achieving the U.S. Green Building Council’s Gold Certification on new buildings.
All of this came together for us in the renovation of the Leland FOB.
For more than 30 years, Walter P Moore has been an industry leader in engineering buildings under high wind loads. Our
Research and Development (R&D) team, under the direction of Larry Griffis, has advanced the state-of-the-art through close working relationships with leading wind consultants like RWDI. Our goal has been to take performance-based design (PBD) principles beyond earthquake events to the design of buildings under wind forces. Together, we’ve conducted extensive exploratory and analytic research.
In 2010, Walter P Moore joined the design-build team of Gensler and Gilbane Building Co. to renovate the GSA’s Leland
FOB. Rather than demolish this 22-story building, we proposed a new and innovative approach: Performance-Based Design (PBD) linked to wind forces. PBD has been successfully applied to buildings in earthquake zones, but never, to our knowledge, for wind events. With the concurrence of the GSA, Gensler, and Gilbane, now it would be.
The renovation was also planned to replace the existing façade with blast resistant cladding, strengthen the structure, refresh the interior, and improve energy efficiency. Furthermore the building would remain occupied, start to finish.
Since wind-based performance design was beyond conventional design approaches, we enlisted our R&D experts to guide analysis and design. They incorporated field conditions data into an analytical model that our structural engineering team then used to prepare the project construction documents. Throughout, our secure design team provided consulting advice and design to ensure the new structure and façade met current requirements for blast resistance and building resilience under a terrorist attack. By applying PBD principles to the renovation of the Leland Building, our team virtually eliminated costly structural strengthening, yet still met the intent of current building codes, both federal and local.
MORE THAN SKIN DEEP
The GSA also wanted to refresh the look of the 1983 precast tower with a modern façade, while simultaneously creating an enclosure that protected occupants. The fact that the building remained occupied made removal and replacement of the existing precast impractical. In response, the design team specified a new blast-resistant curtain wall system mounted over the existing precast cladding. Our design for the support of the new curtain wall system satisfied the structural resistance requirements against wind and blast forces. This lowered removal costs and time. It also reduced construction waste and alleviated the risk of opening the building to the elements, even briefly.
Federal tenants were sequentially moved within the building (there were two unoccupied floors) to allow renovations to progress two floors at a time. The sequencing demanded careful coordination among all team members, with much of the work performed during off-hours and weekends.
Since we couldn’t anticipate all conditions, we incorporated a high degree of adaptability in our design and detailing. The contractor adapted our solutions to actual field conditions as they were uncovered without waiting for tailored solutions.
IN PURSUIT OF PLATINUM
Understanding that GSA wanted to pursue a LEED rating, we applied our expertise in structural sustainability. One of the most meaningful contributions was our wind-focused PBD approach. By rescuing the building from demolition and replacement, we demonstrated the elimination of 1.5 million tons of concrete and 175,000 tons of reinforcing steel. This quantity of structural materials would’ve produced approximately 350,000 tons of cradle-to-grave C02 emissions – and consumed considerable landfill space.
In seeking a LEED Platinum rating, the highest of all the ratings, Walter P Moore contributed to project sustainability in other ways, including the design of support systems for photovoltaic panels atop the garage. The panels produce energy while shading cars. Ultimately our approach yielded a more efficient repair program and saved the project considerable time and money, while employing green building standards. In late 2015 the project achieved LEED Platinum certification.
Walter P Moore, Gensler, Gilbane, and GSA demonstrated that innovation, passion, stewardship, and even an extraordinary experience are all possible when teamwork guides a project, especially a green one.
AND THERE’S MORE TO THE STORY.
The wind PBD research initiative Walter P Moore led has now been validated by a real project. And the industry has taken note. Recently, this approach was studied by ASCE SEI Technical Administrative Committee on Performance of Structures. And Dr. Finley Charney at Virginia Tech is working with a PhD student to advance the research.
Furthermore, ours is the first team to earn an “Innovation in Design” LEED credit for a PBD approach for wind loads. We’ve set a standard of sustainable performance to which others can aspire when pursuing LEED credit for PBD on future projects. This is significant given the substantial and immediate environmental savings of the wind-based PBD approach.