# 9 | Installation in a precast concrete culvert

Installation of a WA-3930 flexible cofferdam in a precast concrete culvert.
Flexible Water-Gate© WA-3930 cofferdam installed in a concrete frame. No ground anchoring.
Fixing the left end of a flexible Water-Gate © WA-3930 cofferdam against the wall of a precast concrete culvert.

Attachment points at both ends and reinforcement of ground roughness

Installation in a frame is more difficult because you cannot operate from the bank of the stream.
The laying area must be prepared before deploying the cofferdam.
The deviation can be done by pipeline under the dam (See Case # 1) or by a spillway placed on the edge of the ridge (See Video).

Flexible Water-Gate© cofferdams. Diagram of an installation in a concrete culvert | Case #9

The stages of the Maneuver

  1. Clean the laying surface
  2. Prepare 3 anchor points on each wall
  3. Lay logs of gravel on the ground to increase the friction forces
  4. Route the flexible cofferdam
  5. Unroll the cofferdam
  6. Unfold the canvas. Please note that the leading edge must always be kept out of the water!
  7. Hang the 4 angles of the flexible cofferdam on the walls
  8. Position the canvas correctly between the two walls and over the sandbags
  9. Place the leading edge at the bottom of the water. Coordinated action!
  10. Check that the canvas goes correctly, without tension, on each side to the wall.
  11. Ballast the leading edge and angles
  12. Ridge edge: place the clamps in the corners to avoid creases and position the flotation accessories
  13. Fixing the leading edge against the walls
Hanging of the 4 angles of the flexible Water-Gate© WA-3930 cofferdam on the walls.
Place bags of gravel on the ground under the Water-Gate© flexible dam to increase the friction forces.
Fixing the leading edge with a plank pressed against the vertical wall.

Removal | Wearing a life jacket compulsory!

Remove all the fasteners on one side.

Raise the leading edge to run water under the cofferdam.

The cofferdam begins to slide under the upstream thrust.

When the flow is considerably reduced, all fasteners are removed on the opposite side.

Removal of a flexible Water-Gate© cofferdam. The leading edge is raised to pass water under the cofferdam and reduce friction forces.