S. Bang

Suction piles for mooring of mobile offshore bases

As part of the feasibility study of constructing mobile offshore bases (MOBs), suction piles are currently being studied to provide the necessary mooring capability for this very large floating structure. MOB position will be controlled by dynamic positioning (DP) during operation. However, during repair, storage, and lay-up periods, or for hybrid mooring in combination with DP, conventional mooring techniques need to be considered. For this reason, suction piles are currently being investigated analytically and experimentally as one option to provide necessary mooring resistance. This paper discusses the laboratory model testing program, development of an analytical solution for successful installation of suction piles in the seafloor, and verification of the analytical solution through field tests.

The Effect of the Nail Skew Angle of Soil Nailing Wall

A finite element method of analysis utilizing the generalized plane strain approach has been developed to analyze three dimensional stress, strains, and displacements of skew soil nailing walls. This paper explains the fundamentals of analytical approach and the effect of the nail skew angle. Analytical computer parametric study has been conducted to investigate the effects of the nail skew angle of the soil nailing wall. As a results of this study, the generalized plane strain finite element solution method is proved to be versatile enough to easily incorporate the complicated geometry and loading condition as well as the non-linear material properties.

Analysis of anchor mooring lines in cohesive seafloor

An analytical solution method capable of determining the geometric configuration and developed tensile forces of mooring lines associated with fixed plate/pile or drag anchors embedded in cohesive seafloor has been developed. The solution method is capable of analyzing multisegmented mooring lines embedded in layered cohesive seafloor soils, utilizing a systematic iterative solution search method based on specified boundary conditions. The results of the developed analytical solution method have been verified through comparisons with the centrifuge model tests and field tests and were found to be very effective.

Horizontal Capacity of Embedded Suction Anchors in Clay

An analytical solution has been developed to estimate the horizontal pullout capacity of embedded suction anchors in clay seafloor. Validation has been made through comparisons with the centrifuge model test results. The results indicate that the horizontal pullout capacity of the embedded suction anchor in clay increases, reaches its peak and then starts to decrease as the point of the load application moves downward. The effect of flanges on the horizontal pullout capacity is also found to be significant.Copyright

Analytical parametric study on horizontal loading capacity of suction piles

An analytical parametric study has been conducted to identify the relative significance of several pertinent parameters that are thought to govern the horizontal loading capacity of suction piles. The parameters studied include: the point of horizontal load application, diameter of flange, pile diameter, seafloor soil strength, pile diameter to length ratio, and layered soil properties. Results of the analytical parametric study on each parameter are summarily included and discussions are provided, which can be used in the future for the optimum design of suction piles.

Embedded Suction Anchors For Floating Breakwaters

Embedded suction anchors were used to provide necessary resistance for mooring a floating breakwater system. The embedded suction anchors and the mooring lines were designed using the methods developed by the US Navy. The validity of the mooring line design method was previously made through experimental field and centrifuge model tests. The validity of the design method for the embedded suction anchor resistance was made through centrifuge model tests as part of this study.

Horizontal Pullout Capacity of Embedded Suction Anchors in Sand

An analytical solution has been developed to estimate the horizontal pullout capacity of embedded suction anchors. Validation has been made through comparisons with the centrifuge model test results. The results indicate that the horizontal pullout capacity of the embedded suction anchor in sand increases, reaches its peak and then starts to decrease as the point of the load application moves downward. The effect of flanges on the horizontal pullout capacity is also found to be significant.© 2006 ASME

Field Installation and Pullout Test of Embedded Suction Anchors

The field installation and pullout tests of an embedded suction anchor were conducted inside the Okpo Harbor located along the southeastern coast of South Korea in 2003. The embedded suction anchor was made of steel with an outside diameter of 1.91 m, length of 2.5 m, and thickness of 3 cm. It was installed by a 9.25-m-long suction pile attached at the top of the anchor. During installation of the embedded suction anchor and retrieval of the suction pile, the water pressure inside the suction pile versus the pile embedded length relationship was carefully measured. In addition, during the embedded suction anchor pullout test, the load versus anchor vertical displacement relationship was measured. The measured pullout capacity was then compared with the analytical prediction. The analytical solution was selected from various available solutions of deeply embedded plate anchors available from the literature through detailed comparisons with the results from geotechnical centrifuge model tests on embedded suction anchors. Comparison indicated that the predicted embedded suction anchor resistance matched reasonably well with the field test result.

PERFORMANCE OF EPOXY-COATED REINFORCED EARTH STRIPS

Abstract The laboratory pull-out test results of epoxy-coated and galvanised ribbed reinforcing strips are reported and compared. The results have been used to predict the developed tensile stresses within the reinforcing strips of recent reinforced earth retaining wall construction using a numerical finite element method of analysis. Comparisons with field measurements have also been made.

Pullout Capacity of Suction Piles in Clay Under Eccentric Vertical Loads

As part of a study on the determination of the suction pile vertical pullout loading capacity, five centrifuge model tests have been conducted on a model suction pile embedded in clay. Details of the centrifuge model test procedures and results are described. Variable in the centrifuge model tests includes the point of the mooring line attachment which was varied from the top to the bottom along the side of the model suction pile. The effect of this parameter on the suction pile vertical pullout capacity is described and discussed in detail. Test results indicate that the loading capacity increases, reaches its peak, and then decreases as the loading point moves downward.Copyright