Optimal arrangement of viscoelastic dampers for seismic control of adjacent shear-type structures
Xiao HUANG
0
1
Hong-ping ZHU
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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.
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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)