**Abstract**

Recent studies about liquefaction initiation are widely encountered in the literature in terms of utilizing the dynamic triaxial tests under harmonic loading and site response of liquefied zones. Sandy-like or clayey-like behavior is important for estimating the liquefaction susceptibility but there are other factors related to cyclic loading characteristics such as frequency content and stress level. Besides, 1-D ground response analyses are employed to understand the behavioral transmission through the soil column in liquefiable areas. The study here focuses on two main aspects of the liquefaction. The first part consists of the estimating of the pore pressure generation under irregular excitations, whereas the second part aims to assess the efficiency of the building codes predicting the nonlinear site response in liquefied prone areas. The laboratory results show that the frequency content has big influence on the liquefaction at varying stress levels. Moreover, literature models have discrepancies to estimate the pore pressure generation under different types of loading. Regarding the site response, it was indicated that equivalent linear approach is incapable of predicting the seismic behavior of soil column; therefore, nonlinear ground response must be run instead, and the IBC is the most effective one to match the nonlinear analysis results.

**Keywords:** liquefaction, pore pressure generation, nonlinear site response, dynamic soil behavior, building codes
