doi:10.3850/978-981-08-7920-4_S2-S40-cd
Efficiency of Seismic Damping Devices for Braced Structures
Mario Uros, Marta Savor and Josip Atalic
Department of Technical Mechanics, University of Zagreb/Faculty of Civil Engineering,
Zagreb, Croatia.
ABSTRACT
This paper describes the influence of dampers on structural response due to the dynamic earthquake
load for a typical multistory steel structure with braces. Responses of different kinds of
dampers are considered, depending on the excitation. The main purpose of structure isolation
is to ensure elastic response of the structure while at the same time the areas of expected large
plastic deformations and loss of input energy should be localized. Firstly, we consider viscous
dampers which will be implemented in the models of earthquake bracing. Parameters defining
damping force-velocity relations are varied in the numerical models. After the implementation
of viscous dampers the Wen rheological model will be applied. With this kind of model we can
control the initial stiffness of the damping device in elastic response and also the stiffness after
yielding. This model describes more appropriately the response of real damping devices, but it
is more complex for numerical analyses. Earthquake load comprises a wide range of frequencies
significant for structures. Inthispaper thiskindof loadismodeledwith a timehistoryrecordof the
real earthquake recorded at the Lexington Dam station during Loma Prieta earthquake in 1989.
Additionally, as a simplification, the real earthquake excitation is replaced by a harmonic function
with frequencies in the range of dominant eigen-frequencies. Forces and displacements obtained
by conducted analyses are compared for differentmodels in order to evaluate damper efficiency.
Keywords: Viscous damping, Bracing, Seismic load, Force-displacement hysteresis.
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