Torsional Response Induced by Lateral Displacement and Inertial Force

Eccentric distribution of stiffness, damping, and mass of a structure, and spatially non-uniform ground motion input to a long or large base mat of a structure are well-known causes of torsional response. We have discovered that the torque generated by horizontal displacement and perpendicular inertial force, which we call the Q-Δ effect, can be a cause of torsional response. We formulated the equation of motion of a single finite-size mass-linear elastic shear and torsion spring model and clarified the resonance condition of the torsional response to sinusoidal ground acceleration. Time-history response analysis verified that the torsional response forms beat and the maximum torsional response of the simulation result agrees with that theoretically predicted. Further time-history response analysis conducted of white noise ground acceleration showed that even one-directional white noise ground acceleration can induce torsional response in a linear elastic system without any structural eccentricity

Editorial: Innovative methodologies for resilient buildings and cities

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EACS 2016 paper - Shaking Table Tests of Cooperative Control between an Active Mass Damper for a Building and Semi-Active Damper for a Base-Isolated Floor Using a Small-Scale Specimen

<div>EACS 2016 Paper No. 136<br></div><div><br></div>To reduce the amount of earthquake damage, the effectiveness of cooperative control between two controllers (one for the building and another for the equipment) was verified using a shaking table test. We employed a Kalman filter and the linear quadratic Gaussian strategy to minimise the amount of damage under strong ground motions, and the two controllers share the quantities of the state variables of the building and equipment. A three-storey specimen, which comprise a building (the main system) with an active mass damper and a base-isolated floor (a subsystem) with a semi-active oil damper, represents a 15-storey building of a data centre on a real scale. As a result of the shaking table test, we confirmed that implementing cooperative control reduced the relative displacement between the main system and subsystem without increasing absolute acceleration