DYNAMIC CROSS INTERACTION BETWEEN TWO FOUNDATIONS UNDER HORIZONTAL VIBRATIONS

Abstract

An experimental study has been carried out to study the dynamic cross interaction between two urlidentical foundations under horizontal vibrations through a dry, dense sand medium. For this purpose their response were measured with the accelerat-ion recording instrument — Pen recorder. The experiments were conducted in dense sand deposit in e tank (size 2.5m x 1.20m x 1.25m). Two plates (size 20 cm x 20 cm x 5 cm for each) of steel, having each its weight as 15.400 kg, were used as the machine foundations. During experi-ments, these plates were excited with D.C. motor — oscillator system. The experiments were conducted (i) the one plate was being excited i.e. with a .certain frequency of excitation and the effect of this excitation was observed on the other plate, (ii) Both plates being excited, one with varying frequencies and other at fixed frequency, and observation of acceleration induced were taken at both plates (iii) The above two types of experiments were repeated for plates having single pile of diameter 20 mm and length of 20 cm, 30 cm, 40 cm. The spacing between the two plates, representative of the foundations for machine, have been varied in these experiments from 20 cm to 50 cm in steps of 10 cm.