SYSTEM-IDENTIFICATION OF THE HUALIEN LSST MODEL STRUCTURE

This paper discusses system identification of a 1/4-scale nuclear reac tor containment Soil-Structure Interaction system (SSI system) based o n forced vibration tests conducted by an exciter, For both NS and EW e xcitations, response components orthogonal to the exciting directions were fairly large because of inhomogeneity of the supporting soil, so, before applying the system identification procedure, the concept of ' Principal Axes (D-1, D-2)' was introduced for the SSI system. The test s results were then transposed to the principal axis directions so tha t the orthogonal components disappeared.(1) The system identification procedure was applied to these principal axis directions. As a result, fundamental frequency, damping factor and mode shape with fixed-base condition were obtained. A mathematical model was thus established by adjusting the calculated fundamental frequency and mode shape with fix ed-base condition to these derived from the test results, The mathemat ical model will be used in the correlation analysis of both forced vib ration tests and earthquake observation records, (C) 1997 John Wiley & Sons, Ltd.