Geology Reference
In-Depth Information
Chapter 2
Performance-Based
Seismic Design:
A Search-Based Cost Optimization
with Minimum Reliability Constraints
Oscar Möller
University of Rosario, Argentina
Fabián Savino
University of Rosario, Argentina
Marcelo Rubinstein
University of Rosario, Argentina
Ricardo O. Foschi
University of British Columbia, Canada
ABSTRACT
An approach is presented to structural optimization for performance-based design in earthquake engineer-
ing. The objective is the minimization of the total cost, including repairing damage produced by future
earthquakes, and satisfying minimum target reliabilities in three performance levels (operational, life
safety, and collapse). The different aspects of the method are considered: a nonlinear dynamic structural
analysis to obtain responses for a set of earthquake records, representing these responses with neural
networks, formulating limit-state functions in terms of deformations and damage, calculating achieved
reliabilities to verify constraint violations, and the development of a gradient-free optimization algo-
rithm. Two examples illustrate the methodology: 1) a reinforced concrete portal for which the design
parameters are member dimensions and steel reinforcement ratios, and 2) optimization of the mass at
the cap of a pile, to meet target reliabilities for two levels of cap displacement. The objective of this
latter example is to illustrate model effects on optimization, using two different hysteresis approaches.
INTRODUCTION
objective (e.g.,the total cost), with constraints
specifying minimum reliability levels for each
performance requirement. Three performance
levels are normally considered in earthquake en-
gineering: serviceability, life safety and collapse.
The objective of the present Chapter is to pres-
ent a procedure for performance-based optimiza-
tion of a preliminary design, taking into account the
Structural optimization for performance-based
design in earthquake engineering aims at finding
optimum design parameters (e.g.,dimensions of
structural members, steel reinforcement ratios
for concrete structures, characteristics of energy
dissipation devices) corresponding to a minimum
Search WWH ::
Custom Search