Browsing by Subject "Drag embedment anchor"

Now showing 1 - 2 of 2

Experimental in-plane behavior of a generic scale model drag embedment anchor in Kaolinite test beds
(2011-05) McCarthy, Katelyn Barbara; Gilbert, Robert B. (Robert Bruce), 1965-; Rathje, Ellen M.
The trajectory and capacity are key components of the design of drag embedment anchor and drag-in vertically loaded anchors. This experimental testing program quantifies two factors that describe the anchor trajectory and capacity: the equilibrium bearing factor (Ne) and the tangential bearing factor (Ne). These factors can aid in the development of a numerical model of anchor behavior. A magnetometer device is used to track the orientation and location of the anchor during drag embedment. The results of the experimental testing program were compared with the results from a predictive model. The experimental program consisted of drag embedment tests with various testing conditions including different anchor line diameters and different initial pitch orientations. The results with the different anchor lines indicated that thinner anchor lines cause the anchor to dive deeper in the soil. The different initial pitch results indicate that regardless of the initial pitch of the anchor, the anchor rotates to a unique pitch trajectory within 2 fluke lengths.
Performance of drag embedment anchors dragged through remolded clay and loaded at various horizontal orientations
(2009-12) Lynk, John Michael; Gilbert, Robert B. (Robert Bruce), 1965-; El Mohtar, Chadi
Drag embedment anchors (DEAs, or anchors) are used as foundations to secure mobile offshore drilling units (MODUs) in soft clay soils on the sea floor. In 2004 and 2005, Hurricanes Ivan, Katrina, and Rita caused the mooring failures of 17 mobile offshore drilling units moored with anchors. Since then, a great deal of research has been conducted regarding anchor performance and reliability. This report provides an overview of anchor research and industry practice to date, and discusses the results of two research experiments to assess anchor performance. One experiment investigated the effect that embedding anchors in the same soil path several times had on bearing force. The second experiment investigated what effect changing the direction of the horizontal load vector relative to the anchor shank had on embedded anchor bearing force. The results of these experiments suggest that remolding clay may have an effect on anchor bearing force capacity, and that repeatable results are obtainable when testing the effect of changing the direction of applied horizontal load.