Seismic Risk of Church Belfries Supported on Seismic Isolation Systems

Abstract

ABSTRACT The seismic risk of historical structures provided with seismic isolation devices is a key aspect to protect people and part of our world heritage. However, the development of empirical fragility functions for church belfries with seismic protection control systems remains insufficient. In this study, the seismic response, fragility functions, and seismic demand risk are investigated for church belfries supported on isolation systems. The study introduces a comprehensive formulation for assessing the seismic risk of church belfries equipped with seismic isolation systems for protection during near- and far-field seismic excitations. It is found that linear viscoelastic and bilinear seismic isolation systems significantly reduce maximum relative accelerations and displacement demands of the church belfries. It is also found that linear viscoelastic seismic isolation systems are more effective to reducing the seismic demands caused by low to high seismic excitations from near- and far-field earthquakes. These results can assist designers, restorers, and decision-makers to select adequate configurations or seismic mitigation measures for belfries to prevent significant economic losses and fatalities and to protect our historical heritage.