Reduction of Vibrations Applied on Structures - Results of Chamber Tests with the Use of Tire Derived Aggregate

This paper presents results of laboratory (medium scale) tests on models simulating a 'concrete footing - subsoil' system. Their goal was to investigate the effectiveness of a cushion made of scrap tire rubber granulate to reduce vibrations applied on the concrete footing. The pad foundation was placed in two types of subsoil: one consisted of sand, the other of sand and a tire rubber layer placed directly under the footing. The models were built in a box 73 x 73 cm wide and 50 cm high, which was then subjected to vibrations by means of a vibration table. The kinematic excitation of vibrations and the response of the footing were examined in the domains of time and frequency. The analysis allowed to estimate the effectiveness of reduction of vibrations dependently on amplitude and frequency of excitation. Additionally, the phase angle between the excitation and response of the model was measured for the main frequency of vibrations. It has been proved that the effectiveness of the scrap tire rubber layer does not depend substantially on the amplitude of excitation, but it does increase for higher frequencies of excitation.The tested solution may constitute an alternative for traditional vibration isolation systems with vertical screens placed close to the source of vibrations or isolations built-in the structure of a building. Its application will be cheap, easily accessible and sustainable.