Project Description

# 6 | U-shaped cofferdam | Rivers

The leading edge is kept out of the water to prevent the dam from filling up before placement is complete.
Aerial view. Water-Gate© installation in U | Installation in a river parallel to the current.
Upstream view. Water-Gate© installation in U | Installation in a river parallel to the current.

Installation parallel to the watercourse or U-shaped cofferdam

This is the preferred installation for riverbank construction and works that only use a section of the river/rivers that cannot be totally blocked.

batardeau en parallèle de la rivière

How to perform the installation?
The stages of the Maneuver

  1. Preparation of the installation area
    Remove sharp objects, remove river mud/vase, position rocks or sandbags if the ground is slippery to increase the friction forces, install stops downstream if the current is strong, position the ballast bags upstream for the maneuver, clean the banks of the river.
  2. Preparation on the bank
    Unroll the flexible cofferdams, unfold them, and attach them to one another.
  3. Positioning in the river
    Pull the pre-attached cofferdams to the desired location keeping the leading edge out of the water.
    Position the cofferdam as desired (L or U or diagonally).
  4. Immersion
    Immerse the leading edge to the river bed.
    Stand on the leading edge until the cofferdam becomes pressurised.
  5. Mooring
    Secure the leading edge’ metal rings with stakes to facilitate placement until the flexible cofferdam is pressurized.
  6. Ballast
    Weigh down the leading edge with ballast bags or stones taken from the watercourse.
  7. Securing the installation
    If the banks are vertical, attach the ends of the removable cofferdam so that they do not fall back into the water.
  8. Drainage of the work area
    Start pumping the space to be dewatered.
U-shaped cofferdam - Construction site - View from the bridge upstream
U-shaped cofferdam - Construction site - View from the left bank
U-shaped cofferdam - Construction site - View from upstream