Notes on the Sears Tower Lecture

Introduction

• Over 25,000 people enter the Sears Tower daily.
• It has 104 elevators (some double-decker) servicing 110 floors.
• Tallest building in North America, previously the tallest in the world until 1998.

Dimensions and Observation Deck

• Height: 1,450 ft.
• Impressive observation deck with visibility up to 50 miles (includes parts of Illinois, Indiana, Wisconsin, and Michigan).
• Over a million tourists visit the Sky Deck annually.

Unique Elevators

• Fastest elevators: 1,600 ft/min, reaching the 103rd floor from the basement in about 60 seconds.
• Building includes offices, private dining, conference facilities, post office, retail, and restaurants.

Infrastructure and Maintenance

• Size: 4.5 million sq ft, nearly the length of five football fields.
• Requires extensive maintenance with 110 janitors, 100 security guards, 25 engineers, and 3 electricians.
• Complex electrical and plumbing system with 50,000 miles of wiring and 25,000 miles of plumbing.
• Automated window washing systems for 16,100 windows.

HVAC and Comfort Control

• Temperature control monitored by engineers to ensure comfort across different floors (e.g., from 65°F at the bottom to 50°F on higher floors).
• Five large chillers providing 4,800 tons of refrigeration.
• No recorded power losses in the building's history.

Historical Context

• Built as Sears Roebuck's headquarters in 1968 to accommodate growth.
• Sears was the leading retailer, competing with JC Penney and Montgomery Ward.
• Original mail order business established by Richard W. Sears in 1887.

Architectural Design and Construction

• Architect: Skidmore, Owings & Merrill; key figures: Bruce Graham (architect) and Fazlur Khan (engineer).
• Innovative "bundled tube" design allowed for taller and more efficient structures.
• Construction began in August 1970, with meticulous planning and execution to ensure structural integrity.

Construction Challenges

• Unique challenges included transporting large prefabricated units and managing weather conditions that affected work schedules.
• Topping out ceremony occurred on May 3, 1973, marking completion of the building's structure.

Post-Construction Era

• Opened in 1974 with 40% occupancy by Sears employees.
• The building was designed for efficiency but the transition led to social disconnections among employees.
• By 1988, Sears put the tower on the market due to changing retail dynamics.

Renovations and Current Status

• New ownership led to renovations in 1990, adapting the building for new tenants and enhancing security post-9/11.
• The tower remains an iconic symbol of Chicago and continues to host tenants and tourists alike.

Conclusion

• The Sears Tower is a monumental achievement in architectural design and engineering, remaining a significant landmark in Chicago's skyline.