Used to ensure a levelled position and provide stability during grouting, IQIPs Jacket Pile Gripper (JPG) has been applied in the constructions of offshore jacket foundations for decades. Furthermore, in recent years, increasingly strict Early Age Cycling standards have made JPGs and FEA simulations essential to demonstrate and secure compliance.
As a temporary equipment welded or bolted onto the jacket structure, the JPG minimises movement between the foundation pile and jacket leg or sleeve during grouting and curing. It does so by creating a temporary clamped connection between pile and jacket thereby also offering an optional jacket levelling function. Crucially, with regard to Early Age Cycling, the JPG also provides the possibility of maintaining relative movement at the grout-steel interface to a maximum of 1mm until sufficient grout strength is reached. This is required to adhere to the DNVGL standards of 2018.
“Learning from the past, some grouted connections have shown signs of damage related to the curing conditions; damages such as cracks that can have catastrophic effects on the lifespan of a foundation, and that’s why this standard originated,” explains the project manager adding: “In the last five years or so, Early Age Cycling has become an increasingly hot topic all over the world, from the North Sea to Taiwan. We have proven through several projects that we can comply with the strict requirements, and that’s incredibly important to our clients, especially in the wind industry where you want the lifespan of foundations to be as long as possible.”
Originated in 2014, the DNVGL standards were further increased in 2016 and now limits global relative displacement to 1mm.