Notes on the Sears Tower Lecture

Introduction

• The Sears Tower, now known as Willis Tower, is located in Chicago and attracts over 25,000 visitors daily.
• It features 104 elevators, including double-decker ones, to service its 110 floors.

Historical Significance

• Once the tallest building in the world until 1998, surpassed by the Petronas Towers in Malaysia.
• Stands 1,450 feet tall, offering views up to 50 miles from its observation deck.
• Attracts over a million tourists annually.

Architectural Features

• The tower is a 4.5 million square foot skyscraper in Chicago's Loop, housing offices, restaurants, and retail stores.
• Contains:
  • 2,232 steps to the top
  • 796 laboratories
  • 16,100 windows
  • 50,000 miles of electric wiring
  • 25,000 miles of plumbing
  • 145,000 light fixtures

Maintenance

• Managed by a team of 110 janitors, 100 security guards, 25 engineers, and electricians.
• Window washing done by automated rigs that can wash 16,100 windows under certain weather conditions.
• Staff monitors HVAC systems to maintain comfort across the tower's many floors, which can vary in temperature.

Construction Background

• Built by Sears Roebuck and Company, the tower was a response to the company's rapid growth post-WWII.
• The decision to build a large headquarters stemmed from a desire to make a statement as the leading retailer.
• Construction began in 1970; the foundation needed to be deep due to the building's weight.

Design and Engineering

• Designed by Skidmore, Owings & Merrill, featuring a "bundled tube" system for structural efficiency.
• Comprised of nine tubes that support the building's height and design.
• Construction involved advanced planning and coordination, including prefabricated steel units for quick assembly.

Construction Challenges

• Experienced setbacks due to weather and accidents during construction, including a near-miss with falling materials.
• The tower was topped off in 1973 with a ceremony attended by thousands, including Sears employees.

Post-Completion Changes

• In 1990, after Sears sold the building, it underwent renovations to appeal to new tenants.
• Lobby redesign and security upgrades followed the September 11 attacks in 2001.

Current Status

• Despite losing its title as tallest building, the Sears Tower remains iconic and a symbol of Chicago.
• Still maintains the tallest antennas in the world, extending 287 feet above the roofline.

Conclusion

• The Sears Tower is a monumental achievement in architecture and engineering and continues to represent the ambition and history of Chicago.