COMBINED PROTECTION OF BRIDGES EXPOSED TO EARTHQUAKE AND FLOOD DISASTERS WITH NEW RB-UPGRADED ISOLATION SYSTEM

Abstract

Combined and extensive experimental and analytical study devoted to development of an integrated earthquake and flood protection (EFP) bridge system was performed. It represents an extension of the integral research project led by the fourth author, conducted in the Institute of Earthquake Engineering and Engineering Seismology (IZIIS), Ss. Cyril and Methodius University (Skopje), during three and a half years, in the frames of the innovative NATO Science for Peace and Security Project “Seismic Upgrading of Bridges in South-East Europe by Innovative Technologies (SFP: 983828)”, involving five European countries and led by the fourth author. The presently introduced EFP bridge system represents a specific, extended segment of the integral research. The upgraded, seismically isolated (USI) system with integrated space flange (SF) energy dissipation (ED) devices has been developed as a mechanical passive concept to provide harmonized response of bridge structures to earthquakes. It was formulated as an adaptive system, which follows the adopted concept of global optimization of seismic energy balance, through utilization of newly designed dissipation devices as a supplementary damping level to bridge isolation. The new EFP-bridge system is based on obligatory incorporation of the following four integrated complementary systems: (1) Seismic isolation (SI) system, (2) Seismic energy dissipation (ED) system, (3) Combined earthquake and flood displacement limiting (EFDL) system composed of new and experimentally tested RB devices and (4) Uplift protection system (UP). With the extensive experimental quasi-static cyclic tests conducted by simulated, gradually increased displacement amplitudes, there were confirmed very stable hysteretic responses of the created prototype models of rubber buffer (RB) devices applicable for efficient protection of common and isolated bridges exposed to either strong earthquakes or flood disasters. Following the upgrading of the seismically isolated (USI) bridge system with energy dissipation devices, the adopted original rubber buffer (RB) devices represent an important additional line of defense against abrupt loadings due to earthquake and flood disasters.