Geology Reference
In-Depth Information
Chapter 1
Life Cycle Cost Considerations
in Seismic Design
Optimization of Structures
Bora Gencturk
University of Illinois at Urbana-Champaign, USA
Amr S. Elnashai
University of Illinois at Urbana-Champaign, USA
ABSTRACT
The life-cycle cost (LCC) of a structure in seismic regions, which includes the initial and the post-
earthquake repair cost, is a critical parameter for structural engineers and other stakeholders. The
LCC analysis has been gaining prominence in recent years since civil infrastructure sustainability has
been identified as one of the grand challenges for engineering in the 21
st
century. The objective of this
chapter is to first identify the components in LCC evaluation that directly affect the outcomes, and pro-
pose strategies to improve the reliability of the analysis. The shortcomings of existing studies on LCC
optimization of structures are identified. These shortcomings include simplified analysis techniques to
determine the structural capacity and earthquake demand, use of generalized definitions for structural
limit states, and inadequacies in treating uncertainty. In the following, the problem formulation and
a brief review of existing literature on LCC optimization of structures are provided. A LCC model is
presented, and techniques are proposed to improve the above mentioned shortcomings. Finally, LCC
analysis of an example reinforced concrete (RC) structure is employed to illustrate the methodology.
INTRODUCTION
zation of the properties of individual elements to
find the optimal solution. In shape optimization,
the contour of the boundary of a structural domain
is optimized while keeping the connectivity of
the structure the same, in other words, no new
boundaries are formed. Topology optimization
is the most general in the sense that both the size
Structural optimization problems may be divided
into three classes: sizing, shape and topology opti-
mization. In sizing optimization, the locations and
number of the structural elements are fixed and
known. Usually, the problem is reduced to optimi-
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