Optimal arrangement of viscoelastic dampers for seismic control of adjacent shear-type structures

Journal of Zhejiang University-SCIENCE A, Jan 2013

The optimal arrangement of viscoelastic dampers (VEDs) used to link two adjacent shear-type structures under seismic excitation was investigated. A two-step optimal design method is proposed. First, optimal parameter expressions of the Kelvin model are used to calculate the optimal stiffness and damping coefficient of the VEDs. Then, using the two-step optimal design method, taking the quadratic performance index as the optimization objective, the optimal arrangement of the dampers is determined. General rules about the optimal arrangement of the VEDs were obtained. The results show that the placement of only one damper between two adjacent shear-type structures should be avoided; if more than one damper is used, they should be distributed on the top and lower floors of the structures. Optimization of the number of dampers had little effect on response reduction. The most important factor was the optimization of the placement of the dampers. Through comparative study, for buildings of equal and unequal heights, the optimal parameters of dampers from parametric studies were shown to match the theoretical results for different numbers and placements of dampers. The level of response reduction was shown to be sensitive to the damping coefficient of the dampers.

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Optimal arrangement of viscoelastic dampers for seismic control of adjacent shear-type structures

Xiao HUANG 0 1 Hong-ping ZHU 0 1 0 Hubei Key Laboratory of Control Structure, Huazhong University of Science and Technology , Wuhan 430074, China) 1 School of Civil Engineering and Mechanics, Huazhong University of Science and Technology , Wuhan 430074, China) ( 2 Project supported by the National Natural Science Foundation of China (No. 51178203), and the National Science Foundation for Distinguished Young Scholars of China (No. 50925828) Zhejiang University and Springer-Verlag Berlin Heidelberg 2013 The optimal arrangement of viscoelastic dampers (VEDs) used to link two adjacent shear-type structures under seismic excitation was investigated. A two-step optimal design method is proposed. First, optimal parameter expressions of the Kelvin model are used to calculate the optimal stiffness and damping coefficient of the VEDs. Then, using the two-step optimal design method, taking the quadratic performance index as the optimization objective, the optimal arrangement of the dampers is determined. General rules about the optimal arrangement of the VEDs were obtained. The results show that the placement of only one damper between two adjacent shear-type structures should be avoided; if more than one damper is used, they should be distributed on the top and lower floors of the structures. Optimization of the number of dampers had little effect on response reduction. The most important factor was the optimization of the placement of the dampers. Through comparative study, for buildings of equal and unequal heights, the optimal parameters of dampers from parametric studies were shown to match the theoretical results for different numbers and placements of dampers. The level of response reduction was shown to be sensitive to the damping coefficient of the dampers. - With rapid economic development, there are more large and high buildings in modern cities, resulting in inadequate separation between adjacent buildings. When two closely spaced adjacent structures are subjected to strong earthquakes, they may collide (Kasai and Maison, 1997; Abdullah et al., 2001). Using energy dissipation devices to connect adjacent structures has proved to be an effective measure to avoid collisions between such buildings and to absorb some seismic energy (Bhaskararao and Jangid, 2006a; 2006b; 2006c; Takewaki, 2007; Bharti et al., 2010; Patel and Jangid, 2011; Roh et al., 2011). Passive control devices are efficient for energy dissipation (Lavan and Levy, 2006; Trombetti and Silvestri, 2006; Silvestri and Trombetti, 2007). Trombetti and Silvestri (2007) investigated the applicability of a novel scheme for inserting viscous dampers in shear-type systems, and provided insights for the effective addition of viscous dampers in mechanical dynamic systems. Viscoelastic dampers (VEDs) are an efficient kind of passive control device for suppressing vibration and dissipating energy, with the advantages of simple installation, low cost and stable performance. There has been a series of studies on adjacent structures coupled with VEDs under seismic excitation. Xu et al. (1999) carried out a theoretical investigation of earthquake-resistance performance of adjacent buildings connected by VEDs defined by the Kelvin model, and obtained the optimal parameters of dampers through extensive parametric studies. Kim et al. (2006) investigated the effect of installing VEDs in places such as seismic joints or building-sky-bridge connections, and found that the displacements of structures were significantly reduced. Zhu and Iemura (2000) studied 2-single-degree-offreedom (SDOF) structures connected by VED under white noise excitation, and gave the analytical formulas for determining the optimal parameters of VED, which were determined from the mass ratio and the natural frequency ratio of 2-SDOF structures. Zhu et al. (2011) and Ge et al. (2010) extended the analytical formulas based on 2-SDOF structures to those of 2-multiple-degree-of-freedom (MDOF) structures, and found that total optimal parameters of VEDs between 2-MDOF structures were determined by the total mass ratio and the modal frequency ratio of the structures. Thus, the total optimal parameters of VEDs between 2-MDOF structures can be directly calculated using theoretical expressions. However, the controlling effect of dampers depends not only on the optimization of the output forces, but also on the placement of the dampers. Where and how many dampers are placed on the structures will have a significant effect on their ability to reduce the responses of structures (Singh and Moreschi, 2002). Ok et al. (2008) studied the optimal design of hysteretic dampers that enhance the seismic performance of two adjacent structures. However, there have been few studies of the optimal arrangement of VEDs between adjacent structures. In previous studies, dampers have generally been placed on one floor (Kim et al., 2006) or uniformly placed on all floors (Xu et al., 1999; Ge et al., 2010; Zhu et al., 201 (...truncated)


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Xiao Huang, Hong-ping Zhu. Optimal arrangement of viscoelastic dampers for seismic control of adjacent shear-type structures, Journal of Zhejiang University-SCIENCE A, 2013, pp. 47-60, Volume 14, Issue 1, DOI: 10.1631/jzus.A1200181