A method for uniform upgrading of isolated bridges with complex root devices

An experimentally proved method for efficient seismic upgrading of isolated bridges exposed to very strong multi-directional near-field and far-field earthquakes is presented in this paper. The advanced capability of the upgraded bridge system was achieved by application of the developed uniform complex root (CR) energy dissipation devices. The new uniform complex root (UCR) bridge system was fully validated based on seismic tests on experimental models and analytical response simulation studies. The UCR system integrates the advances of seismic isolation and energy dissipation and represents an advanced technical solution for efficient protection of bridges located in seismic areas of the highest seismicity. The tested large-scale model of the UCR bridge system had double spherical rolling seismic bearings (DSRSB) as seismic isolation devices, while qualitative improvement of the seismic performances was achieved through the use of the created uniform CR energy dissipation devices. Extensive seismic testing of the UCR bridge model was conducted under simulated effects of near-field and far-field earthquakes, respectively.