Numerical Investigation of a New Method for Seismic Control of Structures
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pISSN 1226-7988, eISSN 1976-3808 www.springer.com/12205
DOI 10.1007/s12205-020-2368-0
Structural Engineering
Numerical Investigation of a New Method for Seismic Control of Structures Mohamad Shahrokh Abdi
a
, Masoud Nekooei
a
, and Mohammad-Ali Jafari
b
a
Department of Civil Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran Structural Department of Transmission and Distribution Research Center, Niroo Research Institute (NRI), Tehran, Iran
b
ARTICLE HISTORY
ABSTRACT
Received 4 January 2020 Accepted 3 August 2020 Published Online 29 October 2020
Vertical mass isolation (VMI) method is used for the seismic control of structures. In this method, the entire structure is considered to be a combination of two mass and stiffness subsystems with an isolator layer located in-between. A magnetorheological (MR) damper is used as the isolator layer to control the structure. The semi-active control technique is applied to control the MR damper based on the applied controlling voltage. Several single degree of freedom structures with the same masses and main periods of 0.5, 1.0, 2.0 and 3.0 seconds are studied. Finally, a comparison between the results of this method with three passive control methods was performed. Results indicated that the semi-active control method based on maximum voltage of 9V will reduce, on average, the maximum roof displacement by 25% and 51% more than the Copt and passive-off methods and is equal to the passive-on method at 9V. However, the efficiency of the semi-active method in controlling the maximum absolute acceleration of the roof and the base shear of the structure was on average 28% and 45% lower than the Copt and passive-off methods, respectively and 2% higher than the passive-on method.
KEYWORDS Seismic control Vertical mass isolation Stiffness Magnetorheological Semi-active Passive control
1. Introduction The resonance phenomenon occurs when the natural period of the structure lies in the range of dominant periods of earthquake accelerations. Because the flexibility of the structure increases via seismic isolation, the natural period of the structure also increases (this is called the periodic shift). This periodic shift causes the resonance not to occur and the seismic acceleration responses to be reduced (Skinner et al., 1993). To achieve the periodic shift, the flexibility and damping ratio of the structure must be increased. Coupling adjacent buildings is one structural control method which can mitigate responses due to seismic excitation. Applying control drives progressively through two unique structures results in the general responses decreasing (Bhaskararao and Jangid, 2006). In terms of installing the control devices, smart structural technology were applied for seismic control of the structure because the traditional seismic resistant devices were ineffective. By using this technology the seismic resistant capacity increased and the dynamic energy dissipated through these devices enabling the structure to withstand CORRESPONDENCE Masou
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