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It is common practice in laboratory tests for the assessment of the liquefaction potential of sands to convert the irregular acceleration time-history to an equivalent number of uniform stress cycles. For this, a number of methodologies exist which are mainly based on Miner's (1945) accumulated damage concept. Miner’s theory states that the damage that a material undergoes is not affected by the location of a cycle of stress within the loading history. However, soil is a nonlinear material with a stress path-dependent response. The composition of the loading history in terms of stress cycles and their magnitude should therefore have an influence on sands’ liquefaction resistance. To shed more light on this, the recorded base ground motion from the Chi Chi, Taiwan, seismic event of the 20th September 1999 is used in non-linear elasto-plastic plane strain effective stress-based finite element analyses of a hypothetical homogeneous soil deposit consisting of Nevada Sand. The irregular surface acceleration time-history is then converted to an equivalent number of uniform as well as non-uniform amplitude cycles at different percentages of the maximum shear stress and single element undrained simple shear tests are numerically simulated. The soil response is investigated to assess the accuracy of the empirical procedures on the response of sands to liquefaction. The results suggest that the empirical methods may lead to non-conservative conclusions.