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ABSTRACT
Considering the soil-structure interaction phenomena, in case of the rigid structure founded on deformable ground, some important changes occur in its response values. Some specific aspects are investigated: kinematic and inertial interaction effects, the fundamental period of a structure, the response spectra that take into account the interaction effects, the transfer function between the structural relative displacements (at the top) and the free-field motion, the differences from the free field motion to the structure input motion, understanding of the distribution of forces and displacements in the structure etc.
The evaluation of soil-structure interaction effects is made through the difference between the actual response of a structure, from seismic monitoring and theoretical analysis, and the response of the structure with a fixed base, and it also result from the spectral ratios top/free field and top/base. Seismic instrumentation of building is used for seismic data acquisition, both on the seismic characteristics of the site and on the dynamic response characteristics of structure.
Keywords: Seismic monitoring, soil-structure interaction, response spectra
INTRODUCTION
SOME SOIL-STRUCTURE INTERACTION ASPECTS
Considering the soil-structure interaction phenomena, in case of the rigid structures founded on deformable ground, some important changes occur in their structural response values and the following observations are made:
* the corresponding periods of vibration analysis that consider soil-structure interaction are greater than those without the consideration of the interaction (the soil is not a deformable support);
* the required number of modes of vibration in order to characterize the modal participating mass ratio for some degrees of freedom of structure is different in these two cases, with and without SSI;
* the story drift is higher for the case with the consideration of soil-structure interaction; the allowable value of relative displacement level is higher than all the values of the calculated story drift ratios;
* a modal analysis with and without P-Delta and with and without SSI puts into evidence some differences in the first periods.
Concerning the features of soil-structure interaction, its implications and the evidence of soil-structure interaction from earthquake records, they were presented and discussed in several papers [1], [2], [3].
UTILIZATION OF SEISMIC INSTRUMENTATION
Seismic instrumentation of buildings is a specific form of monitoring and represents a modern, complex and multilateral system for seismic data...