A New Passive Energy Dissipation System For The Hollow Floor Structure And Seismic Reduction Analysis

Seismic design of high-rise buildings is always a main concern which related to thesecurity of the whole structure. Due to the advantages of light weight and highstrength, concrete hollow floor gains its popularity in large span high-rise structures.A new passive energy dissipation system based on the hollow floor and the TunedRotary Mass Damper (TRMD) is proposed herein combining the characteristic ofhollow floor. The TRMD are placed in the hollow-box to take full advantage of thespare room of hollow floor. The TRMD adopted in this paper is composed of a balland a unidirectional arc path. The ball is initially located at the bottom of the arc pathand begins to roll along the arc path when the device is subjected to base inputs.Therefore, the energy input to the structure from dynamic loads could be absorbedthrough the rolling motion of the ball and dissipated through the friction between thesurface of the ball and the path.Specifically, a differential equation of translational motion of thesingle-TRMD-controlled structure is derived by the Lagrange’s variational method.Next, numerical simulations of the controlled system are implemented using theNewmark-method. The results indicate the TRMD could effectively reduce theseismic response of structures to different earthquake accelerations. Further, Theequation of motion of multi-TRMD-controlled structure is also derived. The effects ofseveral parameters including the numbers of TRMDs, the orbit radius, the radius ofthe oscillators, the coefficient of rolling friction and the damping ratio of structuresare presented. With regard to the translation-torsion coupled structure, the dampingprinciple is slightly different from that of translation structure, since it has anadditional freedom of torsion which affects the motion of the ball in the TRMD.Similar theoretical investigation and numerical analysis are conducted on thetranslation-torsion coupled structure. The results demonstrate that the TRMD couldreduce the structure translational and torsional responses to different earthquakeacceleration. Moreover, the reduction of both responses is approximately the same.Parameter analysis however shows that the same parameter has different effect onthese two kinds of response. According to the inconsistent seismic reduction effects of TRMD to differentearthquake accelerations, the random dynamic response of the damper system isstudied. Specifically, Monte Carlo Simulation is conducted both for the tranlationalcontrolled-structure and the translation-torsion coupled controlled-structure. Theresults exhibit that the damper system has an remarkable vibration-suppressing effect,and decreases the displacement standard deviation of structure sharply under whitenoise. Then, statistical linearization is employed in the calculation of the equivalentlinear dampering ratio. Based on the preceding studies, the TRMD-structure transferfunction is derived by equivalent linearization techniques. Promising agreementbetween Monte Carlo Simulation and Statistical linearization results is observed.