Home » Business & Industrial » The Brooklyn Bridge was Built with the Help of Pressurized Caissons. Several Workers were Killed or Permanently Injured Because of it.
Brooklyn Bridge Caissons

The Brooklyn Bridge was Built with the Help of Pressurized Caissons. Several Workers were Killed or Permanently Injured Because of it.

Underground tunnels and bridge foundations below the water table are some of humanity’s most amazing civil-engineering structures. The working spaces, or caissons, are pressurized with compressed air during construction to keep out groundwater, and laborers known as sandhogs pass through pressure locks into and out of the caissons. But what are pressurized caissons?

The construction of the Brooklyn Bridge used a pressurized caisson. This is a watertight retaining structure. It resulted in numerous workers being killed or permanently injured by decompression sickness, also known as caisson disease.

What is the Pressurized Caisson?

A caisson is a watertight structure that serves as a foundation’s anchor. You need to construct a pier. This pier can be either floating or fixed. A caisson will be used as the structure’s base on the body’s water floor if it is a fixed pier.

Because it provides stability, a caisson can be an important component of any construction project. A caisson can be used to distribute the load evenly where the ground can and will shift due to the weight of a new structure. This allows the building to provide an even cushion rather than settling differently depending on how the soil beneath it fluctuates.

Caissons are vertically drilled into bedrock to support bridge abutments, whereas tunnels are horizontally drilled and used for roads, railroads, subways, water, and sewage. 

Tunnels, which were previously excavated by gangs of sandhogs using picks, shovels, and explosives, are now excavated by tunnel boring machines (TBMs), which have massive rotating cylinder heads with toothed faces that cut through rock and muck as the TBM is forced along. Only the space in front of the TBM face is pressurized in favorable rock formations and used only for maintenance and tooth replacement. This reduces pressure exposure and significantly improves safety.

A pneumatic or compressed-air caisson provides dry working conditions, which is preferable for concrete placement. It is also well suited for foundations where other methods might cause adjacent structures to settle.  (Source: Foundation Structures

Health Cautions Associated with the Use of Pressurized Caissons

Construction workers who exit the pressurized environment of the caisson must decompress at a rate that allows symptom-free release of inert gasses dissolved in body tissues if they are to avoid decompression sickness, a condition first identified in caisson workers. It is dubbed caisson disease in recognition of occupational hazards.

During the construction of the Brooklyn Bridge, which was built with the help of pressurized caissons, numerous workers were killed or permanently injured by caisson disease. Other risks include barotrauma of the ears, sinus cavities, and lungs and dysphoric osteonecrosis.  (Source: Foundation Structures

The Caisson Installation

A caisson can be installed in a variety of ways. Some are built and installed on-site, whereas others can be built off-site and moved to their installation location.

The location and type of caisson will determine the installation method. The placement location may need to be prepared at times. This is when a cofferdam is built. A cofferdam is occasionally used to clear an area so a caisson can be installed. A cofferdam is essentially two dams placed on opposite sides of a river.

They aim to cut off the water supply to a specific area, resulting in a dry space. These are temporary structures designed to help, not as long-term solutions. (Source: Foundation Structures

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