Dutch engineering company TWD has developed a new internal parachute system designed to reduce pile run risks during offshore wind foundation installation, with testing carried out at Marin. Pile run occurs when a monopile or pin pile suddenly penetrates the seabed faster than intended after losing soil resistance, generating high loads on installation equipment and creating safety risks for vessels and personnel.
The Pile Run Parachute (PRP) is an internal hydrodynamic damping system that slows the descent of a falling pile by restricting water flow through a controlled top orifice. Installed inside the pile, the removable and reusable system uses a sealed hemispherical insert designed not to interfere with hammer operations during pile driving.
Scale testing at Marin used a 400kg pile in a 1:10 configuration, with more than 30 test setups evaluating pressure relief concepts, orifice size, parachute slackness and connection stiffness.
According to the test results, the PRP reduced pile run speed by up to 26 times and lowered terminal velocity to levels comparable with crane operations. Two pressure regulator concepts reduced dynamic amplification factor loads by around 10% and 16% respectively, while pile driving tests confirmed the system had negligible impact on hammer efficiency.
