Caisson (engineering)

The term caisson ( also French Caisson ) denotes a box ( container ), which has been used since the mid-19th century in underwater work.

It is a hollow, cylindrical or rectangular structure which is sunk as a foundation or as a work space in the water.

The caisson is built usually on land and then towed and sunk to the required location on the water. It is often necessary, the caisson by a certain amount in the basic lower. In this case it is used as a work space, which is open downward. To prevent the surrounding water from entering, the cavity is put pneumatically under a pressure matched.

The material of the reason can be taken away - the caisson can be lowered as a result more and more. When the required depth is reached, the cavity - filled - mostly with tremie concrete. In this way, can arise such as a bridge abutment.

Another possibility is the use of tunneling. Here, several caissons are sunk side by side and waterproof linked. Then the side walls are removed, so as to realize a continuous tube.

For people who work in such, placed under pressure Senkglocke, there is a not insignificant health risk. If the pressure drop when leaving the caisson is given too rapidly, gas bubbles can form in the blood. This so-called caisson disease can lead to paralysis or even death. In the meantime, this risk is counteracted by workers make their way to their work in the caisson in a pressure chamber in which the pressure over a longer period is continuously lowered.

Buildings that have been realized with the help of caissons

  • Old Elbe Tunnel, Hamburg
  • Bay Bridge, San Francisco
  • Brooklyn Bridge, New York City
  • Drogdentunnel, Oresund connection
  • La Pallice
  • New Elbe Tunnel, Hamburg
  • Rotersand
  • Saalachstrasse Kraftwerk Bad Reichenhall, lock system
  • Scheldt overhead line crossing Doel
  • Skye Bridge, Scotland
  • Spreetunnel Friedrich Hagen, Berlin
  • Underground Development System ( UES ) of the Bundestag, Berlin
  • Lake Lipno
  • Stralsund overhead line crossing
  • Tiergartentunnel, Berlin
  • Tower Bridge, London
  • Transbay Tube, San Francisco
  • Westminster Bridge, London

Also the film "Water for Canitoga " (1939 ) explains the principle of the caisson and its dangers: in the finale of the film Hans Albers device when working in a caisson due to large pressure differences in a life-threatening situation.