The behaviour of plate anchors in sand

The work, presented in this thesis describes an investigation into the behaviour of plate anchors embedded in dry sando Previous theoretical, laboratory and field scale experimental work is reported. From the review of this work apparent discrepancies were found between the results, and these were attributed to the fact that certain properties of the soil had not been considered in the previous theories. These parameters have been considered by the author in the development of an approximate method for the determination of anchor ultimate loads. Extensive experimental model testing programme was carried out in uniformly deposited sand using air activated sand spreader and raining devices. In a main series of tests anchors with diameters up to 75 mm were embedded at depth upon diameter ratios up to 25 in dense, medium dense and loose sand and subjected to vertical and inclined loading. Anchor loads and displacements and surface deformations were recorded. Photographic tests were carried out to determine the failure surfaces within the sand mass. From the analysis of the results it is shown that the behaviour of a plate anchor in sand is a function of a large number of factors. These factors include depth of embedment, anchor width, sand density, relative density and angle of internal friction. A finite element method of analysis was used for predicting the anchor load-displacement relationship and the distribution of stresses within the sand mass. The previous theories are shown to be of limited use when applied to the present test results and those of others. The approximate method developed is checked against the present experimental results and satisfactory agreement is obtained. The method is checked against previous model and field test results for shallow, deep, vertical and inclined cases and good agreement is found. Conclusions are drawn and it is suggested by the author that in the absence of an exact method the approximate method can be used to predict ultimate uplift capacity of plate anchors. For the sand used in this investigation design curves for calculation of anchor ultimate loads are presented. Suggestions are made for future experimental and analytical work