Processed parameters from sensors located on seismically isolated buildings (maximum acceleration, spectral acceleration and oscillation periods) are compared against free-field ground motion to evaluate the improvement in seismic response for these buildings. The study is carried out for three structures in Bucharest, the capital city of Romania. The data used in this research correspond to moderate magnitude earthquakes, 4.2 ≤ MW ≤ 5.5 generated from the Vrancea-intermediate-depth seismic area, with focal depths greater than ~90 km. The methodology helps to evaluate amplification/reduction in the seismic motion, and confirmed that base-isolation devices reduce the seismic parameters’ amplitudes of the structure directly above the isolating layer. The effectiveness of the base-isolation technique is further assessed by comparing the amplitude of the seismic parameters recorded under and above the earthquake protection devices. The results show a clear decrease in the values right above the isolating system, supporting the efficiency of base-isolation systems. The outcomes provide necessary empirical data for refining seismic design and improving the resilience of critical structures. The work contributes to the mitigation of the seismic risk in the city area, thus targeting a more resilient urban community and sustainable city through implementation of modern base-isolation systems for the retrofitting of vulnerable buildings exposed to a high risk of seismic hazards.
Apostol et al. (Tue,) studied this question.