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
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.