FLAC model free- field incremental dynamic analysis

Nonlinear dynamic analyses were performed to evaluate the effects of ground motion duration on the dynamic response of a pile-supported wharf subjected to liquefaction-induced lateral ground deformations. The numerical model was first calibrated against recorded data from a centrifuge test and then used in an incremental dynamic analysis using a suite of spectrally matched motions with different durations. The nonlinear dynamic analyses were performed for three loading scenarios: combined effects of inertial loads from the wharf deck and kinematic loads from ground deformations, inertial loads only in the absence of liquefaction, and kinematic loads only in the absence of deck mass. The analysis results provided insights on the relative contribution of inertial and kinematic demands on the response of the wharf with respect to motion duration. It was found that the interaction of peak inertial and kinematic loads increases with motion duration. However, the response of the wharf supported by relatively flexible piles having a small diameter (0.6 m) was found to be primarily governed by kinematic demands in long-duration motions. The differences between the effects of motion duration on the response of small-diameter flexible piles and stiff shafts with a large-diameter (2 m) are discussed in the final report.