6 minute read
A new day
from CCR Issue 9
Derek Larsen of Bendheim helped architects select about 2,700 feet of architectural glass for a renovation project at Willis Tower in Chicago.
Photography by Ed M. Koziarski
5-year, $500 million project transforms Chicago’s historic Willis Tower
By Thomas Renner
Establishing architectural charm in a building that is five football fields tall is not an easy assignment. At the Willis Tower, which soars 1,451 feet in the air, creating a warm and cozy aura is a huge ask. But that was the primary objective in the recently completed transformation of the iconic Chicago landmark. Construction teams at the building, which held the mantle of the world’s tallest building for nearly 25 years, recently wrapped up the five-year, $500 million redevelopment project.
The scope included introducing 300,000 square feet of new restaurants, retail, entertainment and outdoor terrace space to the existing tower—a transformation that created 125,000 square feet of new tenant-exclusive amenities. It also launched the country’s largest elevator modernization project. The directive to the architect, Gensler, was to create a more welcoming, warmer building. “The space was previously closed off to the street, an approach taken for decades in cities to ensure security,’’ says Gensler architect Marissa Luehring. “It was designed at a time when working people didn’t necessarily live downtown. Willis Tower was primarily a place to go to work, so there was little engagement with the streetscape and within the building. Now, what we’ve done is open the podium back up to the community.” Architects and installers found numerous nuances to consider and puzzles to solve. The 110-story building, which attracts 25,000 daily visitors and hosts 15,000 workers in more than 100 businesses, stayed open during the three-year renovation. “We had all of these foundations and footings, and we had to figure out how to put in a new building that doesn’t have to tie into anything that’s underneath it or on top of it,’’ Luehring says. “And we still had thousands of tourists and thousands of working people coming into the building every single day.” The building, originally known as Sears Tower, opened in 1974 as the world’s tallest skyscraper. London-based Willis Group Holdings bought the naming right as part of its lease (the name was formally changed in 2009). Purchased by Blackstone in 2015 and managed by EQ Office, it now is the third tallest building in the United States. One of the more distinctive architectural choices to help create an inviting approach is a rising staircase with a “red carpet” feel, featuring backlit glass risers. More than 300 square feet of 3-foot x 120-foot safety laminated glass panels by architectural glass manufacturer Bendheim Architectural Glass were included. “It was quite a technical challenge to design and fabricate the glass,’’ says Derek Larsen, Bendheim’s Central Regional Manager. “It could not be fully tempered due to the
Willis Tower, which opened in 1974 as the world’s tallest building, attracts 25,000 daily visitors and hosts 15,000 workers in 100 businesses.
unusual sizes and potential issues with bowing. We also needed to determine the correct opacity for backlighting.” Bendheim manufactured more than 2,700 square feet of customized architectural glass materials for the project. Each of the various glass types achieved distinct architectural objectives. Bendheim’s Gothic glass in a hammered texture softens up partition walls, dividing the space to create unique and more intimate rooms. Houdini glass, one of Bendheim’s standard products, enhances privacy around the tower’s checkpoint area. Double-sided bronze etched mirror acts as a partition wall and 3/4 inch monolithic grey glass was installed in large doors and openings around the security areas. “There were a lot of challenges in this project to get the appearance perfect,’’ Larsen says. “We offered different textures and opacities. Ultimately, we homed in on the correct aesthetic over many design iterations. The project incorporates many glass types, and the end result came out gorgeous.”
— Marissa Luehring, Architect/Designer, Gensler
Exterior improvements added
SkB Architects overhauled the street-level experience and facade. The intent married the goals of the interior changes to make the building more welcoming. According to a fact sheet on the project, “With its new exterior, Willis Tower will offer an inviting and vibrant pedestrian experience while honoring the building’s role as a unique Chicago and American icon. It will create a sense of place, not just a place to work.” A five-story district at the base of the tower, called Catalog, ties the building back to the original owner, Sears Roebuck and Company. EQ Office calls Catalog a neighborhood, with retail, dining and entertainment. “Catalog represents everything we love about Chicago, from the energy of the neighborhoods and the diversity of the city’s design and architecture,’’ says David
Moore, Senior VP and Portfolio Director of the EQ Office. Moore says the space recognizes the pace of change occurring in everyone’s lives and needs to drive lifestyle and experience into the workday. With the addition of Catalog, EQ is furthering its mission to create a new Willis Tower as an urban destination that is the heart of downtown, capturing the vibrancy of the city and delivering the best experiences of life and work to residents and visitors of Chicago. One of the most intriguing design challenges facing architects was creating appeal for all of the various users of Willis Tower, from its daily workers to first-time Skydeck visitors and everyone in between. “It was extremely important for us to celebrate the building and to create a space where everybody knew that they were in Willis Tower,” Luehring says. “Planning-wise, it was all about the cross section of people and how to engage across all of the different levels. We wanted to give everybody a dedicated space for their specific functions while also creating a lot of different forms of vertical transportation and mixing zones.” Since the building remained open during the transformation, architects
Did you know?
Approximately 1.7 million people visit Willis Tower every year. The building, then known as Sears Tower, opened in 1974 and was the world’s tallest building from 1974-1999. It remains the world’s tallest steel-construction building.
Willis Tower at a glance
Willis Tower, Chicago Project details: A five-year, $500 million redevelopment covered 425,000 square feet of the building, which is the third tallest building in the Western Hemisphere. Teams completed work on the interior and exterior of the building, including a five-story district at the base of the building that includes retail, dining and entertainment.
The objective: The overarching goal for project architect Gensler was to create a building that was a more welcoming, warmer building.
Class with Glass: Architectural glass manufacturer Bendheim delivered more than 2,700 square feet of materials for the project, and each brought distinct architectural objectives. Among the most unique was 300 square feet of backlit laminated glass along a staircase that creates a “red carpet” feel to the building.
and construction teams had to work with existing infrastructure. The numbers are overwhelming, including 43,000 miles of telephone cable, 25,000 miles of electrical cable and 25 miles of plumbing. There are more than 100 elevators moving 1,600 feet per minute. “We wanted the experience of the building to really feel like Chicago,’’ Luehring says. “There are so many different types of people in the city, and with Willis Tower being such an iconic building, it is a popular destination, especially for people who are visiting Chicago for the first time. It’s a great place for residents to show off their city and kind of get that cross section of all of Chicago in one place.” CCR
Thomas Renner writes on building, construction and other trade industry topics for publications throughout the United States.
