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Project

Willis Tower Repositioning

Expanding the retail and tourist experience at one of Chicago's most popular tourist destinations.

Lead Contact

Project Details

Project Partners
Blackstone Group & EQ Office
Owner
Gensler
Location
Chicago, Illinois
Completion Date
Area
470,000 ft²
The Willis Tower Repositioning in Chicago. Thornton Tomasetti
The Willis Tower Repositioning in Chicago. Thornton Tomasetti
The Willis Tower Repositioning in Chicago. Thornton Tomasetti
The Willis Tower Repositioning in Chicago. Thornton Tomasetti
The Willis Tower Repositioning in Chicago. Thornton Tomasetti
The Willis Tower Repositioning in Chicago. Thornton Tomasetti
The Willis Tower Repositioning in Chicago. Thornton Tomasetti
The Willis Tower Repositioning in Chicago. Thornton Tomasetti
The Willis Tower Repositioning in Chicago. Courtesy Gensler

Overview

The 110-story Willis Tower (previously known as the Sears Tower) was completed in 1974 becoming the tallest building in the world. The iconic tower held the title for nearly 25 years and has become of Chicago’s most popular tourist destinations. 

The tower's current renovation aims to expand the retail and tourist experience at the building’s first six levels. The plaza will be replaced with a three-story retail structure featuring a winter garden with a grid shell skylight, 300,000 square feet of new retail and dining, a belowground entrance to the Skydeck and a rooftop green space that includes a skating rink during winter season. 

We are providing structural design and façade engineering to Gensler for the retail expansion

Highlights

  • The scope of work includes the design and necessary modifications/ reinforcement of the superstructure and foundations.
  • The work was carefully coordinated with relocating an existing plumbing main and site work to maintain operations of the tower throughout construction.
  • The team is also providing structural analysis and recommendations for the proposed green roof designs.
  • The new three-story podium will feature seven different façade systems and a complex gridshell skylight. The primary skin systems are composed of custom steel and aluminum glazing and stainless steel metal plates.
  • Our façade engineering services include detailing of façade systems and gridshell, specialty glass selection and specification review. The project includes shop drawing and product data review, site and plant visits, and witnessing of field testing during construction.