Design of Base Isolators for a 5-storeyed Building with Isolators Analysis in ABAQUS

Abstract

In recent years considerable attention has been paid to research and development of structural control devices with particular emphasis on mitigation of wind and seismic response of buildings. vibration-control measures i.e passive, active, semi-active and hybrid vibration control methods have been developed in past few years . Passive vibration control helps to keep the building essentially elastic during large earthquakes and its fundamental frequency is lower than both its fixed base frequency and the frequencies of ground motion. Base isolation is a passive vibration control system and helps to reduce the seismic forces at a large scale. Forced vibration analysis was carried out on the framed structure by the use of computer program ABAQUS 6.13 and validating the same experimentally. The isolation system reduces the interstorey drift in the superstructure by a factor of at least two and sometimes by a factor of at least five. Acceleration responses are also reduced in the structure by an amount of although the amount of reduction depends upon the force deflection characteristic of the isolators. Better performance of isolated structure with respect to the fixed base structure is also observed in floor displacements, base shear floor acceleration relative to the ground(less acceleration imparted on each floor and their magnitude is approximately same in each floor), roof displacement. Introduction of horizontal flexibility at the base helps in proper energy dissipation at the base level and reducing the seismic forces in the super structure which are considered during design. For Comparison Building is designed with fixed base and with base isolator , and storey drift , displacement , velocity and acceleration are compared for both the structures . Then Manual Designing of the Isolator is done and analysis of that isolator is done in ABAQUS Software.