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Stewart Technology Associates (STA) offers design services and specialized analytical tools for marine anchors of all types. STA has been at the forefront of anchor research for the last nine years. The computer program STA CHAIN, for calculating the geometry and tension distribution of the anchor chain in the sea bed, was developed for the US Navy in 1988. The computer program STA ANCHOR, for the prediction of drag anchor embedment and holding capacity, was first released in 1991. Programs STA PILE, and STA PULLOUT are for design of pile anchors and plate, or VLA (Vertically Loaded Anchors), respectively. The latest version of STA ANCHOR (released in 1995) has been calibrated for the new generation of VLAs. Collectively, these computer programs enable engineers to design and analyze a wide variety of anchor systems. Analytically it can be shown that conventional modern drag embedment anchors will resist large amounts of uplift in soft soils. This has been demonstrated with full scale and centrifuge tests. Although regulatory agencies are reluctant to accept conventional drag anchor designs which incorporate uplift at the sea bed, it has been demonstrated that such uplift is tolerable and, especially in deep water, enormous cost savings can result.
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