Low-Cost Base-Isolation System for Seismic Protection of Rural Buildings

摘要

A simple low-cost friction base-isolation system is examined for its applicability in reducing seismic vulnerability of rural buildings. Four friction isolation interfaces, namely, marble-marble, marble-high-density polyethylene, marble-rubber sheet, and marble-geosynthetic, were studied. The friction properties of these interfaces were studied under static and dynamic conditions for a range of normal loads from 10 to 50 kN. The average coefficients of friction for all of these interfaces except marble-rubber were found to be in the range of 0.05-0.15. The effectiveness of these isolation systems was investigated both analytically and experimentally for a spectrum-compatible ground motion corresponding to the maximum credible earthquake for the most severe earthquake zone according to Indian standards for earthquake-resistant design. The analytical prediction of seismic response of buildings with such isolation was found to be in good agreement (within 19%) with the experimental observation. It was found that for marble-marble and marble-geosynthetic interfaces, more than 50% reduction in absolute response acceleration at the roof level could be achieved in comparison with the response of the fixed-base structure at the cost of increasing relative sliding displacements at the friction interface. However, these relative displacements were well within the commonly adopted plinth projection (75 mm).