1st Croatian Conference on Earthquake Engineering 1CroCEE 2021

Extensive experimental and analytical research have been performed, led by the third author during three and a half years, in the Institute of Earthquake Engineering and Engineering Seismology (IZIIS), Ss. Cyril and Methodius University in Skopje, in the frame 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 USI-V-MG system representing 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 have been achieved. The seismic response of the isolated bridge segment becomes controlled by simultaneous effects of the present isolation system and the new uniform multi-gap added damping system. Initially, in the paper are presented the original concept, device creation process, production of the first model prototypes, as well as, the original experimental laboratory tests of the main components of the integral prototypes of the developed new uniform V-MG energy dissipation devices. The new multi-gap V-MG devices provide added "adaptive" damping to the common seismically isolated system which generally does not possess sufficient damping capacity. In the following part of the paper, shortly are discussed some unique and original observations resulting from conducted complex shaking table tests of constructed large-scale bridge model. The extensive experimental research program is 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 seismic performances is achieved through the use of novel uniform vertical multi-gap energy dissipation (V-MG-ED) devices.