Grout provides structural support, enhances stability, and facilitates the transfer of loads from the offshore structure to the seabed. It acts as a crucial bonding agent, securing the foundation and preventing any potential movement or instability caused by the dynamic forces of wind, waves, and currents. A well-executed grouting operation ensures the integrity and durability of the foundation, enabling the asset to operate efficiently over its operational lifespan.
The choice of grout material depends on factors such as specific design requirements, site conditions, and engineering preferences. Commonly used grouts include Portland cement, pre-blended material, and lightweight filler material. Different grout types may be used in various sections or layers of the foundation, based on their specific properties and performance characteristics. High-performance blended cementitious grouts are commonly used due to their excellent bonding characteristics and resistance to harsh marine environments. This type of grout is designed to withstand the extreme conditions encountered offshore, including saltwater corrosion and fluctuating temperatures. However, neat Portland cement grout is just as effective in some foundations and has several advantages from an installation and cost point of view.
While grouting plays a crucial role in the construction phase, ongoing maintenance is equally important to preserve the integrity of the foundation. Unlike with bolted connections, once the grout is in place it does not come out and does not need to be replaced during the lifetime of asset; in fact, it gets stronger over time. However, regular inspections of other parts of the foundation and the rest of the structure should be performed to monitor loads, vibration, fatigue stress, temperature, and corrosion to allow for timely repairs and reinforcement if necessary. Grout can be used as a repair tool for areas unrelated to the initial grouted pile connection. Repair and strengthening options include member filling, grouted clamps and cable supports.
Acteon’s marine foundations segment provides market-leading grouting services through LDD. The grouting equipment is versatile to mix all types of bulk and bag-supplied grouts with minimal re-configuration. The project type, vessel, and grout product selected will determine which grout system is provided. Operations, maintenance, and integrity packages are available to include development of site-specific, optimised O&M strategies including inspection, survey, monitoring, repair, and maintenance requirements to ensure that subsea assets safely fulfil their design life. To support the continued growth of offshore wind worldwide, Acteon’s marine foundations segment is investing in research and innovation to optimise offshore installation and grouting techniques and materials.