Abstract
In order to verify the applicability of strain space multiple mechanism model based on finite strain (both total Lagrangian (TL) and updated Lagrangian (UL)) formulations, seismic response analyses are performed on Breakwater No.7 in Kobe Port during 1995 Hyogoken-Nanbu earthquake. Both infinitesimal and finite deformation analyses are performed to examine how the effect of geometrical nonlinearity affects the analytical results. As an input dilatancy parameter in the model, two types of undrained shear strength (20 kPa and 40 kPa) are adopted according to the results of undrained triaxial compression tests. The settlements at the top of the caisson in the infinitesimal deformation analyses are 3.62 m and 2.89 m for the undrained shear strength of 20 kPa and 40 kPa, both of which exceed the upper limit of measurements (2.6 m). In contrast, the computed settlements in the TL/UL formulations with the undrained shear strength of 20 kPa and 40 kPa are 2.46/2.46 m and 1.93/1.88 m, respectively, both of which fall inside the measured range (between 1.4 and 2.6 m). The results confirm that the TL and UL formulations are numerically equivalent and the effect of geometrical nonlinearity has to be accurately considered in predicting the seismic response of port structures such as breakwaters.
