This work focuses some technical activities in the development of new Vertical Load Anchor (VLA) project. A "mud-tank" laboratory is implanted and small-scale anchor models are carried out. The laboratory is fully equipped with sensors and all controlled by computer. The activities also include the carrying out of comparative tests between a Reference Anchor model, similar to a known anchor, and the Developed Anchor model. The tests lead out to the establishment of new anchor geometry, with appropriate characteristics for a good drag-embedment performance in clay, for holding capacity specified.
The very waters Brazilian coast petroleum exploration has demanded the use of semi-submerged offshore platform and many different non-conventional subsystems. In this context, special anchors, such as the Vertical Load Anchor (VLA) are an important nonconventional component for the platform mooring systems. The main advantage of the VLA anchors, when compared with conventional anchors, is the capacity for holding high traction loads. A typical VLA installation procedure, a pull out test, a rope arrangement and emhedment trajectory are schematically shown in Figure la and lb, where, it can be verified the advantage of using smaller mooring system cable lengths. The operation offshore platform scenery is "clean-up" with no longer the use of very lengthly catenary mooring lines and the drastically reduction of the anchorage radius. The VIA anchors usually have high load capacities, which are important economic and operational factors for the offshore platform safety. The high load capacity of the CENO-ROF VLA anchor, about one hundred times its own weight, is assured by very complexes shape and structural arrangement, as it is shown in Figure 2. A fully stress analysis, complemented by Buckling and Fatigue analyses guarantee the structural integrity of the anchor, which should be verified and certified by the Bureau Veritas.
