consideration when calculating the amount of CO2. Nevertheless, this
relationship suggests that the optimization of monetary costs is closely
related to a reduction in environmental costs. This has already been reported
by Paya-Zaforteza et al. [15] for CO2-optimization of RC building
frames aswell as by Yepes et al. [16] for RC retainingwalls. This is a significant
finding since clearly reducing CO2 emissions is economically affordable
with regard to reducing global warming. Moreover, prices are
more sensitive to market cycles, while emissions depend on stricter
manufacturing processes. Therefore, it appears that designs based on
emissions are more stable andmore rational. However, the physical dimensions
and details of the design for cost and emissions optimization
can vary significantly because unit prices and emissions are not in any
proportional relationship to one another.