Cyclic Lateral Loading of Piles; Analysis of Centrifuge Tests

Abstract

In two previous reports (6,7) results were given of a number of cyclic lateral load tests on model piles loaded in a centrifuge. The tests results were obtained in the form of loads and deflections at the top of the pile and readings from strain gauges distributed down the pile; the latter are interpreted in the form of moments. In contrast to field tests, the centrifuge pile experiments are carried out in an extremely uniform medium consisting, in the tests discussed, of dry and wet sand in two test series. The result of this soil uniformity is that moment readings can be represented by a smooth and continuous curve. Erratic data due to alternately dense and loose soil layers are avoided. In the second report (7) the fitting of curves to this data was discussed briefly with reference to the use of a fifth-order spline function. The advantage of the technique is that the curve passes through all the data points in contrast with least squares or linear regression fits. In the latter, general curves are obtained representative of the pile deflections in some way which pass near but not necessarily through the data points. Errors in the data are inherently accepted in this method.

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