Koniambo, New Caledonia
Smithbridge New Caledonia engaged Madsen Giersing (MG) to undertake the design of the cofferdam and the permanent wing wall structures for the Seawater Intake Structure as part of the Koniambo Nickel Project in New Caledonia.
The Seawater Intake is a cast in-situ concrete structure with the plan dimension of 6.25m x 20m. The top of the structure is at RL +4.3m and the base is at RL -4.7m.
MG undertook the design of the cofferdam in which the intake structure was to be built.
The cofferdam consists of a sheet pile wall and internal frames. Part of the design was a step-by-step construction procedure for the installation and removal of the cofferdam.
As the second part of the project, MG provided a cost effective alternative design for the permanent wing wall at the front of the Intake Structure. The total length of wing wall is 26m, located at both sides of the Intake. The first section of wing wall is a 2.8m wide cast in-situ concrete retaining wall which extends out from either side of the Intake. The further extension of the wing wall consists of steel sheet piles and a tie rod anchor system.