ABSTRACT
Dynamic loading is discussed in relation to three different methods. The ‘equivalent linear method’, which is often used in the analysis of embankment structures and important foundation, is described together with a method which allows for a more detailed piecewise linearisation of the material stress-strain relationship. The effect of unloading of a material element may be incorporated by employing an unloading tangential stiffness for the given sub-increment. Certain other problems associated with the selection of appropriate values for the tangent modulus exist, and particularly the problem of obtaining a solution which is consistent with material test results. In practice, stress-strain data are obtained from laboratory tests for either drained or undrained conditions, depending upon the particular problem. The damping element will move, with time, with a velocity proportional to the load carried and deformation within the damping element will allow stress transfer to take place to the frictional element.
