Field experimental investigation on broadband vibration mitigation using metamaterial-based barrier-foundation system

Abstract

Both periodic barriers and periodic foundations can be used as passive isolation measures to reduce the unfavorable vibrations affecting the protected superstructure. Under a certain direction of excitation, the frequency band gaps provided by the periodic barriers and periodic foundations are usually distinguishable due to the different orientations of these subsurface structures. In this study, a series of field tests are conducted to assess the combined usage of the periodic barrier and periodic foundation in a manner to achieve better wave isolation effect. Both periodic barrier and periodic foundation used in this study are made of one-dimensional (1-D) layered periodic material. Using the state-of-art hydraulic mobile shaker (T-Rex), the excitation with various types of input signals can be applied in all the three orthogonal directions at the desired location. The arrangement of motion sensors allows for recording the response of the ground surface and the protected superstructure in all the three directions. The screening effectiveness, quantified as Frequency Response Function (FRF), of the periodic barrier and periodic foundation are discussed separately, followed by an overall evaluation of the wave isolation performance of the system composed of both periodic barrier and periodic foundation. The results show that the filtering capability of the periodic barrier and the periodic foundation is complementary to each other, and the combined usage of the periodic barrier and the periodic foundation is beneficial to mitigating the vibration of the protected superstructure.