A SHORT POSTGRADUATE COURSE ON HEURISTIC DESIGN OF PRESTRESSED CONCRETE ROAD BRIDGE DECKS
This paper deals with a short postgraduate course in automated design and economic optimization of prestressed concrete bridges typically used in public road construction. The course forms part of a recent MSc course in Concrete Engineering which has started in October 2007. The course is concerned first with the basic heuristic algorithms for structural optimization, such as genetic algorithms, ant colonies, simulated annealing, tabu search, threshold acceptance, particle swarm optimization, neural networks, etc. And it then moves to the application of such algorithms to the practical design of real concrete structures such as walls, road portal and box frames, building frames, vaults, bridge piers, abutments and decks. Two design cases are presented. Simulated annealing (SA) is firstly applied to a prestressed concrete precast beam of 30-30 meters of longitudinal spans and 12.00 m of width. The beam has a double U-shape cross-section with beam spacing of 6 m. This example has 59 discrete design variables for the geometry of the beam and the slab, materials in the two elements and active and passive reinforcement. The SA method indicates savings of about 5% with respect to a traditional design. The second type of structure analysed is a 30-30 m prestressed concrete road bridge deck. This example has 27 discrete variables. Threshold accepting method (TA) indicates savings of about 7.5% with respect to the design based on the experience of the bridge designers. Finally, case studies indicate that heuristic optimization is a forthcoming option for improving the design costs of real prestressed bridge decks.