Optimization of high-performance concrete post-tensioned box-girder pedestrian bridges

Abstract

This paper deals with the economic optimization of high-performance post-tensioned concrete boxgirder pedestrian bridges. To this end, a program analyzes and evaluates the structural restrictions following Spanish codes for structural concrete and bridge design loads. This problem includes 33 discrete design variables that define the geometry, the concrete, the reinforcing steel bars and the post-tensioned steel. Various acceptance criteria are proposed to modify a variant of the simulated annealing algorithm with a neighborhood move based on the mutation operator from the genetic algorithms (SAMO). An objective methodology based on the extreme value theory is used to determine the number of experimental tests required to provide a solution with user-defined accuracy as compared to a global optimum solution. Results indicate that the local optima found by SAMO2 fits a threeparameter Weibull distribution and improves the cost results for this structural problem. The minimum value obtained by SAMO2 differed just 0.34% compared to the theoretical minimum value so that, from the structural engineering perspective, the divergence was small enough to be accepted. Highstrength concrete performance was further studied in a concrete strength parametric study to acquire more evidence-based knowledge on its implications for economic efficiency. Finally, the study showed that high-strength concrete decreases the cost by 4.5% and the amount of concrete by 26%.

Optimization of Columns and Bent Caps of RC Bridges for Cost and CO2 Emission

“…Pedro et al [4] used a two-stage optimization approach to minimize the material costs of the steel-concrete composite I-girder bridges. Yepes et al [5] optimally designed the post-tensioned concrete box-girder pedestrian deck to minimize the economic cost. Penadés-Plà et al [6] employed a robust design optimization method to design a continuous prestressed concrete box girder pedestrian bridge.…”