CRITICAL NEAR RESONANCE SHAKING TABLE TESTS OF CONSTRUCTED LARGE-SCALE UPGRADED ISOLATED USI-V-MG BRIDGE PROTOTYPE MODEL

Construction of modern, seismically safe bridge structures represents a permanent activity of the highest importance because bridge structures are important key elements responsible for providing continuous functioning of integral highway infrastructure systems. An extensive experimental and analytical research led by the third author was performed in the Institute of Earthquake Engineering and Engineering Seismology (IZIIS), Ss. Cyril and Methodius University in Skopje, lasting three and a half years, in the frames of the innovative NATO Science for Peace Project “Seismic Upgrading of Bridges in South-East Europe by Innovative Technologies (SFP: 983828)”, involving five countries. The specific project part included development of the innovative upgraded seismically isolated system USI with vertical multi gap V-MG representing an advanced technology for seismic isolation and seismic protection of bridges. By integrating the new uniform, vertical multi-gap (V-MG) energy dissipation devices, qualitative advances of the USI-V-MG system were achieved. The original observations resulting from the conducted complex, unique and critical near resonance shaking table tests of the constructed large-scale bridge model are presented and discussed in this paper. The extensive experimental research program was realized on a bridge model constructed by using the seismically isolated system upgraded with uniform vertical multi-gap energy dissipation devices (USI-V-MG). The installed adaptive system for seismic protection of bridges utilizes originally produced double spherical rolling seismic bearings (DSRSB) as seismic isolators, while qualitative improvement of the seismic performances is achieved through the use of novel, uniform vertical multi-gap energy dissipation (V-MG-ED) devices.