FORCED VIBRATION TEST OF THE HUALIEN LARGE-SCALE SOIL-STRUCTURE INTERACTION-MODEL .2.

A Large-Scale Seismic Test (LSST) programme conducted at Hualien (stif f soil site), Taiwan, has started (Tang et al., 1991) to provide earth quake-induced soil-structure interaction (SSI) data as an extension of the same kind of program conducted at Lotung (soft soil site) (EPRI, 1989). Two tests have been performed: a Forced Vibration Test (FVT) wi thout embedment (Morishita et al., 1993) and the same test with embedm ent. Horizontal excitations were applied in two different directions b oth on the roof slab and on the basemat of a 1/4-scale containment mod el. Vertical excitations were applied on the basemat only. The concept of 'Principal Axes (D-1, D-2) was introduced for the SSI system, and the basic dynamic characteristics of the soil-structure system were ob tained for D, and D,. As an example, resonance frequencies for horizon tal excitations were 4.1 and 4.6 Hz without embedment, and 6.1 and 6.3 Hz with embedment for D-1 and D-2 based on results transformed to pri ncipal axes. Finally, a soil impedance function was obtained by a newl y defined error minimizing method. This function also simulates the cl assic embedment effect. (C) 1997 Elsevier Science S.A.