Notes on the Sears Tower Lecture

Overview

• Daily Visitors: Over 25,000 people visit the Sears Tower daily.
• Elevators: 104 elevators (including double-deckers) serve 110 floors.
• Height: Originally the tallest building in the world (1,450 ft) until 1998.

Observation Deck

• Sky Deck: Offers views up to 50 miles, covering areas in Illinois, Indiana, Wisconsin, and Michigan.
• Tourism: More than a million tourists visit annually.

Building Specifications

• Size: 4.5 million sq ft, comparable to five football fields.
• Stairs: 2,232 steps to the top.
• Staffing: 110 janitors, 100 security guards, 25 engineers, 3 electricians, etc.
• Infrastructure: 50,000 miles of electrical wiring, 25,000 miles of plumbing, 80 miles of elevator cables, and 145,000 light fixtures.

Maintenance Operations

• Window Cleaning: Six automated window washing rigs; washes 16,100 windows.
• Temperature Control: Engineers monitor HVAC systems to manage temperature differences across floors.
• Refrigeration: Five chillers providing 4,800 tons of refrigeration, with multiple zones to control temperatures.

Historical Context

• Purpose: Built as a headquarters for Sears, Roebuck and Company in 1968.
• Growth: Sears was the largest retailer, requiring ample space for operations.
• Founding: Started as a mail-order business founded by Richard W. Sears in 1887.

Architectural Design

• Architects: Skidmore, Owings & Merrill, led by Bruce Graham and Fazlur Khan.
• Design Concept: Utilized the bundled tube system for structural efficiency.
• Floor Plan: 9 bundled tubes, varying heights to enhance aesthetics and functionality.

Construction Process

• Foundation: Required extensive excavation and reinforced concrete.
• Ironwork: Fast-paced assembly, with iron workers achieving two floors per week.
• Safety: Various incidents occurred during construction, resulting in a total of six deaths.

Completion and Occupancy

• Topping Off: Ceremony in May 1973 marking the building's structural completion.
• Occupancy Issues: Shift to a vertical office environment led to employee disconnection.
• Market Changes: By 1988, Sears faced declining sales, leading to the sale of the tower.

Renovations and Security

• Post-Sears Era: The building was renovated for new tenants after Sears' departure.
• Security Enhancements: Upgraded following the 9/11 attacks, including advanced access systems.

Legacy

• Current Status: Sears Tower remains an iconic symbol of Chicago.
• Record Holder: While surpassed in height, retains the tallest antennas in the world.