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Software
for Reliability Assessment and Performance-Based
Design:
A
major project objective is the development of
performance-based design tools, with reliability
constraints. The implementation of
performance-based design requires a definition of
performance, a structural analysis to calculate
the relevant performance variables, and an
estimation of the reliability with which the
performance standard will be satisfied. The
problem is generally controlled by a set of random
variables plus design parameters. In design, these
parameters must be calculated to achieve the
reliability levels sought for each performance
standard.
Research
in the Civil Engineering Department has focused on
the development of software for the estimation of
reliability, given information on the intervening
variables and design parameters, as well as the
inverse problem of calculating those parameters
for prescribed target reliabilities. Two general
packages, RELAN and
IRELAN, have been developed
towards these ends.
Under
this project, both RELAN
and IRELAN have been
adapted using a response surface methodology. Once
the response surface for a given performance
criterion is developed through deterministic
structural analyses, fast and efficient
Windows-based design packages are developed using the general reliability
software. The result is an efficient tool for the
development of engineered wood products and also
for the general design office. EQFRAME is an
example of how RELAN
and IRELAN can be implemented
for the design of frames. EQFRAME
is shown in an example where a dowel connection
has to be designed to satisfy three criteria under
earthquake loading, with prescribed target
reliabilities. The output from EQFRAME are the
design parameters chosen for this case: the radius
of the dowel arrangement, the diameter of the
individual dowels, and their yield strength.
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