Geology Reference
In-Depth Information
Chapter 2
Optimal Placement of
Viscous Dampers for
Seismic Building Design
Jessica K. Whittle
University of Oxford, UK
Martin S. Williams
University of Oxford, UK
Theodore L. Karavasilis
University of Warwick, UK
Anthony Blakeborough
University of Oxford, UK
ABSTRACT
While the use of supplemental damping for improving the seismic performance of buildings has gained
acceptance in recent years, there remains a lack of consensus over how dampers should be optimally
arranged within a structure. The authors review recent advances in damper placement methodology
based on optimisation theory, and present a detailed comparative study of five selected methods: two
using simple empirical rules - uniform and stiffness-proportional damping distributions; and three more
advanced, iterative methods - the simplified sequential search algorithm (SSSA), Takewaki's method
based on minimising transfer function drifts, and Lavan's fully-stressed analysis/redesign approach.
The comparison of the selected methods is based on the performance enhancement of a ten-story, steel
moment-resisting frame. It is shown that even very crude placement techniques can achieve substantial
improvements in building performance. The three advanced optimisation methods show the potential
to reduce interstory drifts beyond the level that can be achieved using uniform or stiffness-proportional
methods, though the influence on floor accelerations is less marked. The optimisation methods studied
show broadly comparable performance, so ease of use becomes a significant factor in choosing between
them. In this respect, Lavan's approach offers some advantages over the others.
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