Concrete dams

Published on 29 January 2008

 

The advantage of concrete is primarily to allow construction of more resistant structures. There are two principle types:
- gravity dams,
- arch dams.
To these may be added buttress dams and multiple arch dams, which are variants of the first two.

  • Gravity dams

As the name indicates, this type of dams uses its weight to counteract the water and hold it. As the resistance properties of the materials changed, the triangular form at the mouth of the structure gradually became standard.

Concrete dam - gravity type
Concrete dam - gravity type
Coupe verticale = vertical section; Injection ou coupure étanche = injection or sealed cut
  • Arch dams

Arch dams are the ultimate in terms of using the properties of concrete to provide resistance. They allow economies of volume of at least 30% compared to gravity dams.

One might compare the shape of these to a bridge which is laid on its side and which is loaded with water instead of vehicles. The resistance stresses are thereby partly transferred to the central arch on the banks, allowing the construction of less voluminous structures, but of equivalent performance.

The foundations, on the other hand, to which a large part of the stresses are transferred, must have superior mechanical characteristics to be able to support this.

Concrete dam - arch type
Concrete dam - arch type
Coupe horizontale = horizontal section; Injection ou coupure étanche = injection or sealed cut
  • Buttress and multiple arch dams

Other forms of arch dams are variants of these first two types. Buttress dams are therefore gravity dams that are lightened from the inside. Multiple arch dams, on the other hand, rest on intermediate supports, for those cases where there is too great a span between the two banks of a watercourse.