Overview
The American Council of Engineering Companies (ACEC) has named Bank of America Tower a Grand Award winner of its 2021 National Engineering Excellence Awards in the category of structural systems. The Bank of America Tower in downtown Houston includes amenities designed to attract a new generation of tenants. To meet the demand for environmentally responsible energy-efficiency workplaces, the project set—and achieved—a sustainability goal previously never achieved by an office property in the United States: LEED v4 Core and Shell Platinum certification.
As structural engineer, Walter P Moore created a cost-efficient structural frame for the 35-story tower that offers spacious column-free floorplates with up to eight corner offices per floor. As civil engineer, they created a water harvesting system that provides irrigation for a 12th-floor urban rooftop oasis. More importantly, the firm pioneered a new environmental accounting method to quantify and achieve reductions in embodied carbon.
The project was the first large-scale commercial development in the U.S. to consider the embodied carbon emissions of the building materials using the Whole Building Life Cycle Assessment. Walter P Moore used the Athena Impact Estimator to quantify the sources of environmental impacts from the building construction and demonstrate that concrete was the dominant driver of embodied carbon.
Based on this analysis, the firm led an integrated effort to minimize the impacts associated with concrete construction. This focused on producing concrete mixes that minimized environmental impact by optimally using cement. The mix design used in the 9,500 cubic yard mat foundation was specifically designed for this project and focused on reducing embodied carbon. The mix alone saved over 3,000,000 lbs. of CO2 as determined by the NRMCA’s regional average. The project also highlighted the need for increased, and standardized, supply chain material transparency data to allow teams to make robust design and procurement choices. Overall, the project achieved a 20% reduction in embodied carbon, a 13% reduction in emissions that cause ocean acidification, and a 35% reduction in ozone-depleting compounds as compared to typical core and shell construction.
Furthermore, the tower fosters social interaction and connection to nature. The 12th-floor landscaped roof garden provides a natural respite for tenants and features native plants that manage stormwater runoff. The tower is also the only building in downtown Houston with natural light that reaches the tunnel level. Walter P Moore designed sloping columns in the levels above to reduce the number of columns in the three-story atrium and enable natural light to penetrate the tunnel level. The result is a deeply daylit space, a public indoor plaza that has become a destination retail environment attracting patrons from all over downtown Houston.
Ultimately, Bank of America Tower became the first project in the U.S.—and the highest-rated project in the world when certified—to achieve LEED v4 Core and Shell Platinum certification.
