Metaheuristic Optimization in Seismic Structural Design and Inspection Scheduling of Buildings - Structural Seismic Design Optimization and Earthquake Engineering - page 159

D PBD2 is by 57% less expensive when the proba-
bilistic formulation is also implemented for 60
records. For the five-story symmetric test ex-
ample, comparing the histograms of Figure 3(a)
it can be noticed that the width of the 90% con-
fidence bounds of the life-cycle cost values, of
design D descr , is much narrower compared to the
other two confidence bounds both for the deter-
ministic formulation while for the probabilistic
one it is D PBD2 design that shows the narrower
confidence bounds. Furthermore, it can be said
that with reference to the mean value of the life-
cycle cost (as shown in Table 6) D PBD1 is by 38%
less expensive compared to D descr ; while D PBD2 is

by 52% less expensive when the deterministic
formulation is implemented for 60 records. On
the other hand, as shown in Table 7, it can be said
that design D PBD1 is by 40% less expensive com-
pared to D descr ; while D PBD2 is by 53% less expen-
sive when the probabilistic formulation is also
implemented for 60 records. Comparing the de-
terministic with the probabilistic formulation with
reference to the median values, they appear to be
increased by 12% to 30% for the eight-story test
example and by 11% to 13% for the five-story
building.

Figure 2. Eight-story test case - Prescriptive vs PBD (a) frequency of occurrence deterministic approach
and (b) frequency of occurrence probabilistic approach, all for the case of 60 records

Figure 3. Five-story test case - Prescriptive vs PBD (a) frequency of occurrence deterministic approach
and (b) frequency of occurrence probabilistic approach, all for the case of 60 records