Lecture Notes: The Construction of the Brooklyn Bridge

Introduction

Mid-19th Century Context: Suspension bridges in Europe faced challenges as their industrial cables frayed in turbulent weather.
John Roebling's Proposal: Proposed the largest and most expensive suspension bridge over New York's East River.
Problem: Overcrowding in Manhattan and congested river traffic.

Hybrid Bridge Model:
- Suspension Bridge Elements: Large cables supported by central pillars and anchors to support long decks.
- Cable-Stayed Bridge Elements: Diagonal cables running directly to support towers for enhanced stability.
- Both elements enhanced stability and reduced weight on anchor cables.
Specifications:
- Deck span: Over 480 meters, 1.5 times longer than any previous suspension bridge.
- Required 5,600 kilometers of metal wire for cables.
- Towers to stand over 90 meters high, tallest in the Western Hemisphere of that time.

Tragic Accident: John Roebling died in 1869 from tetanus after an accident.
Leadership Continuity: Washington Roebling, his son, took over the project.
Pneumatic Caissons:
- Used to build foundations on the rocky river bed.
- Involved pressurized air systems to excavate and place stone, later filled with concrete.
- Difficult working conditions, fires, and decompression sickness ("the bends") affected workers.

Health Issues: Washington suffered from decompression sickness.
Emily Roebling's Role:
- Communicated between Washington and engineers.
- Took over project management responsibilities.

Budget and Schedule Overruns: By 1877, the project was over budget and behind schedule.
Faulty Wires: Cable contractor sold faulty wires, but Roebling's design had failsafes.
Reinforcement: Additional wires were added to ensure the bridge's stability.

Opening: The Brooklyn Bridge opened on May 24, 1883.
Cost and Effort: Took 14 years and the modern equivalent of over 400 million dollars.
Significance: A testament to the resilience and innovation of the Roeblings, still standing today.