Validation of the UEL in a 3D dynamic analysis

For validation purpose, a dynamic 3D analysis on a simple isolated slab is presented. Four UFREIs are used to seismically isolate the square-rigid slab, as seen in Fig. \ref{598382}. To generate 3D behaviors of the system including torsion and rotation during seismic excitation, four UFREIs with significant different stiffness are used in the isolation system. Two models are presented in this section. The reference model employs detailed 3D UFREIs with refined mesh and the second uses the proposed UEL as replacement of each UFREI. The isolated system is then subjected to an accelerogram, which is estimated resulting in a moderate displacement of the base isolators. Finally, the UEL model gives an excellent prediction of the detailed 3D FE model, as shown in the comparative results of top acceleration (fig. \ref{924311}).