Thornton Tomasetti, the international engineering firm, announces that Zurich Insurance Group’s new North American headquarters, a 784,000-square-foot, 11-story office building outside of Chicago, has achieved U.S. Green Building Council® LEED Platinum® certification.

Working closely with architects Goettsch Partners and developer Clayco, Thornton Tomasetti served as the sustainability consultant for the project, which is the largest LEED Platinum Core and Shell v2009 project in the U.S. and the only LEED Platinum CS v2009 project in Illinois.

Key Points

• Thornton Tomasetti played a key role in developing and analyzing project strategies to achieve LEED Platinum certification and a 62.7% whole building energy cost savings. The building includes multiple green roofs, energy efficient technologies, rainwater harvest and re-use, accommodations for electric and low-emitting vehicles and native landscaping with more than 600 trees on 40 acres.

• To verify performance and optimize the façade for reduced energy consumption, Thornton Tomasetti provided computational fluid dynamics (CFD) modeling on the ventilated double-wall façade on the lower portion of the south-facing, three-story cafeteria. The 4.5-foot-wide double wall with integrated shades is designed to reduce solar gains in summer, while increasing the gains in the winter, as well as to improve daylighting, resulting in an estimated 33% energy savings in the adjacent space.

• The building is composed of three primary “bars” stacked and arranged to maximize views of the surrounding landscape and to optimize solar orientation. Thornton Tomasetti provided detailed daylighting studies using Honeybee software to evaluate the effects of automated interior blinds and fine-tuned the depth of the exterior shading devices for each orientation. The analysis optimized the depth of the shades for energy performance, which reduced peak solar gain for better thermal comfort and the size of the mechanical systems.

Executive Quotes

Gunnar Hubbard, FAIA, LEED Fellow, Principal & Sustainability Practice Leader, Thornton Tomasetti

“We are delighted to have played a role in Zurich Insurance’s new LEED Platinum headquarters. Through our collaboration with the architects and developer, we were able to achieve a level of LEED certification that is unprecedented in Illinois and pairs seamlessly with Zurich’s commitment to sustainability.”

Joseph Dolinar, AIA, Partner, Goettsch Partners

“Thornton Tomasetti’s expertise in high performing building systems was instrumental in achieving our goal of LEED Platinum certification. The firm’s energy modeling of the building, targeted studies of façade shading concepts, daylighting studies and double-skin wall analysis enabled us to optimize the façade design and greatly improve the overall building energy performance.”

Supporting Materials

» Thornton Tomasetti
» Sustainability Practice
» Zurich Insurance Headquarters

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About Thornton Tomasetti (www.ThorntonTomasetti.com)
Thornton Tomasetti is a leader in engineering design, investigation and analysis serving clients worldwide on projects of all sizes and complexity. Through its 10 complementary practices, Thornton Tomasetti addresses the full life cycle of a structure. We have supported clients working in more than 50 countries, with projects that include the tallest buildings and longest spans to the restoration of prized historic properties. Thornton Tomasetti comprises more than 1,200 engineering, architecture, sustainability practitioners and support professionals who collaborate from offices across North America and in Asia-Pacific, Europe, Latin America and the Middle East.