Sand Base Isolation in Seismic Rehabilitation

Base Isolation is one of modern design method in passive control. Base isolators are components which uses in building piers & foundations for reduction of kinetic energy with scattering earthquake induced forces to structures. This effect causes with substitution isolators between buildings and their foundations. Base isolator method usually is applied in prominent and sensitive structures such as bridges, nuclear power plants and otherindustrial structures. one of this case is using segment with low horizontal stiffness but high vertical stiffness in below of foundations, we can increase major period of structure and overcome against natural earthquake frequencies with less base shears (they were major objectives in seismic design). Flexibility of structure causesvibration and oscillation period enhancement and it makes more interval and distance of maximum earthquakeenergy. Flexibility means our structure members have tolerable and considerable plastic deflection before finalcollapse. One of more usable methods for rehabilitation low and mid height structures with high weight and high frequency and more stiffness in previous centuries are application flexibility with base isolators. fundamental of this method is in separating building from ground, induced load because of isolation between structure andground is reduced, flexibility exists in structure piers or between stories, isolators usually have upper period than fixed supports natural periods, this incensement may cause reduce seismic spectrum, isolators have different types and, using of this method in soft soils and consistence of structure period with ground period is not recommended in other words it may cause resonance and intensity

Sand Base Isolation in Seismic Rehabilitation Keywords:

Sand Base Isolation , Seismic Rehabilitation and retrofit , passive Control , Flexibility