Shake table testing of un-reinforced brick masonry building test model isolated by U-FREI

Summary This paper presents a detailed study on feasibility of un-bonded fiber reinforced elastomeric isolator (U-FREI) as an alternative to steel reinforced elastomeric isolator (SREI) for seismic isolation of un-reinforced masonry buildings. Un-reinforced masonry buildings are inherently vulnerable under seismic excitation, and U-FREIs are used for seismic isolation of such buildings in the present study. Shake table testing of a base isolated two storey un-reinforced masonry building model subjected to four prescribed input excitations is carried out to ascertain its effectiveness in controlling seismic response. To compare the performance of U-FREI, same building is placed directly on the shake table without isolator, and fixed base (FB) condition is simulated by restraining the base of the building with the shake table. Dynamic response characteristic of base isolated (BI) masonry building subjected to different intensities of input earthquakes is compared with the response of the same building without base isolation system. Acceleration response amplification and peak response values of test model with and without base isolation system are compared for different intensities of table acceleration. Distribution of shear forces and moment along the height of the structure and response time histories indicates significant reduction of dynamic responses of the structure with U-FREI system. This study clearly demonstrates the improved seismic performance of un-reinforced masonry building model supported on U-FREIs under the action of considered ground motions. Copyright © 2015 John Wiley & Sons, Ltd.