ABSTRACT
An equilibrium response to repeated loading has been given the general term “Shakedown” (Sharp & Booker 1984) with the term “plastic shakedown” being used to label the development of
1 INTRODUCTION
Machine foundations require the special attention of a foundation engineer. In addition to static loads due to the weight of machine and the foundation, loads acting on such foundations are dynamic in nature. In this type of foundation, a dynamic load is applied repetitively over a very large period of time and many loading cycles. While the magnitude is small, it is therefore necessary that the soil behavior will be elastic, or else deformation will increase with each cycle of loading until the foundation displacement becomes practically unacceptable. Research into the behavior of soil and shallow foundations subjected to dynamic loads was initiated during the 1960s and 2000s. Theoretical and experimental studies of the dynamic bearing capacity of shallow foundations were reported by researchers. Experimental observation of the load-settlement relationships of square surface foundations supported by sand and clay and subjected to transient loads were reported by Cunny & Sloan (1961) and more recently by Erickson & Drescher (2002). Raymond & Komos (1978) conducted laboratory model tests on strip surface foundations supported by sand and subjected to cyclic loadings of low frequency to determine the relationship between foundation settlement and the number of load cycles. Das & Shin (1996) reported the results of some laboratory model tests conducted to evaluate the permanent settlement of a surface strip foundation on a saturated clayey soil layer, while being subjected to a combination of static and
such an equilibrium state after a number of cycles of response, in which plastic strain accumulated incrementally (Werkmeister et al. 2001; 2005).
