DYWIDAG Helps Supplies Anchors for World’s First Steel and Wood Hybrid Wind Towers
DYWIDAG was hired to help build the first-ever fully-operational wood and steel wind towers for a private owner in the Haute-Marne region of France.
A private owner wanted to install a total of seven wind towers on their property: four made entirely of steel and three made from a hybrid wood and steel construction. The terrain where the towers were to be built was primarily clay/limestone, which would require very heavy concrete and steel foundations, so a first-of-its-kind hybrid approach of a lighter wood and steel construction was proposed. Thanks this hybrid technique the quantity of steel is drastically reduced and so overall the load of the tower.
Stony terrain is best for building wind towers, but this site’s terrain was non-optimal clayey limestone. A large and deep cement weight block would need to be installed for each of the towers’ foundations. Instead, InnoVent, a young design office in the Bordeaux region of France, created a solution so that the feet of the tower masts would not rely on a single steel barrel, but rather on an isotropic shape that allows similar anchoring capabilities out of wood. The spacing of the wooden legs and reduction in structure weight meant the base of the hybrid wind turbine could be built on four piles with a diameter of one meter and 20 meters deep rather than very heavy concrete and steel foundations which weigh approximately 880 tons.
DYWIDAG’s French team was noted for their flexibility in working with InnoVent on the turbines. Several administrative disruptions slowed the project, but the DYWIDAG team worked with the fluid schedule to supply 64 strand anchors for the first two wind towers. The team also performed stressing at 75.200kN.
The first two towers, completed in June 2022, are 87 meters high. The third is still under construction and will have a height of over 90 meters.
Only the base of the hybrid wind turbines differs from a conventional turbine design. Using wood and steel instead of only steel has numerous ecological and sustainability advantages, including:
Smaller footprint on the ground (uses approximately one-eighth of the concrete)
Divide by 3 the amount of steel
Creates 315 fewer tons of CO2 to produce a hybrid turbine compared to standard
Better recycling benefits at the turbine’s end of life