Single Anchors Research Articles

Behaviour of single and multiple underream anchors in a gibson soil : Rowe, R K; Booker, J R University of Sydney, School of Civil Engineering, research report R373, Sept 1980, 54P

An accurate and economical technique for the analysis of buried footings and multiple underream anchors in a non- homogeneous elastic soil is outlined. The method of analysis may be used for quite general non-homogeneous, anisotropic elastic soil profiles although in this paper, attention is restricted to anchors in a soil whose modulus increased linearly with depth. The behaviour of both isolated underreams and multiple underream systems is examined. Consideration is given to the effect on anchor response of non-homogeneity, anchor embedment, layer depth and Poisson's ratio as well as the number and spacing of underreams. The influence of anisotropy and anchor inclination are also discussed. The results from this study are presented in the form of influence charts which may be used as a hand method for estimating the elastic load- displacement behaviour for quite general anchor systems to sufficient accuracy for most practical purposes. The use of the charts is illustrated by two examples (A). (TRRL)

The elastic displacements of single and multiple underream anchors in a Gibson soil

An accurate and economical technique for the analysis of buried footings and multiple underream anchors in a non-homogeneous elastic soil is outlined. The method of analysis may be used for general non-homogeneous, anisotropic elastic soil profiles although, in this Paper, attention is restricted to anchors in a soil whose modulus increased linearly with depth. The behaviour of both isolated underreams and multiple underream systems is examined. Consideration is given to the effect on anchor response of non-homogeneity, anchor embedment, layer depth and Poisson's ratio as well as the number and spacing of underreams. The influence of anisotropy and anchor inclination are also discussed. The results from this study are presented in the form of influence charts which may be used as a hand method for estimating the elastic load-displacement behaviour for general anchor systems to sufficient accuracy for most practical purposes. The use of the charts is illustrated by two examples. Une technique précise et économique pour l'analyse de semelles enterrées et d'ancrages à bases élargies multiples dans un sol élastique non homogèn est esquissée. Il est possible d'utiliser cette méthode d'analyse pour toutes sortes de profils de sols élastiques anisotropiques, non homogènes, bien que cet article se limite aux ancrages dans un sol dont le module augmente linéairement avec la profondeur. Le comportement de bases élargies isolées et de systèmes à bases élargies multiples est examiné. Il est tenu compte de l'effet que produisent la non-homogénéité, l'encastrement de l'ancrage, la profondeur de la couche et le coefficient de Poisson, ainsi que le nombre et l'espacement des bases élargies sur les réactions de l'ancrage. L'influence de l'anisotropie et de l'inclinaison de l'ancrage est également étudiée. Les résultats de cette étude sont présentés sous la forme de diagrammes d'influence pouvant servir de méthode manuelle pour l'estimation du comportement charge-déplacement élastique de systèmes d'ancrage généraux, le degré de précision étant suffisant pour la plupart des applications pratiques. Deux exemples illustrent l'emploi des diagrammes.

Closure to “Single Leg Catenary Mooring and Anchors”

Closure to “Single Leg Catenary Mooring and Anchors”

Discussion of “Single Leg Catenary Mooring and Anchors”

Discussion of “Single Leg Catenary Mooring and Anchors”

Single Leg Catenary Mooring and Anchors

Single leg catenary systems with short scope (ratio of total chain length to water depth) are often required to be designed to resist the dynamic forces due to the movement of the moored vessel. In order to prevent impact loads on the system, it is necessary that the total kinetic energy imparted to the system by the moored vessel is absorbed by the potential energy inherent in the SLC system. The kinetic energy is a function of the velocity or drift of the moored vessel, a known quantity; while the potential energy is a function of the weight of the riser chain, an unknown quantity that must be determined. The critical loading results from a reversal of wind and current forces which cause the moored vessel to move across the mooring area and pass directly over the anchor point. A method is presented which utilizes an energy approach to determine the weight of the riser chain required to prevent impact loads on the system at the maximum excursion at maximum load.