Author(s)

S. Hernandez, D. Marcos, A. N. Fontan & J. Diaz

Abstract

Optimum tendon layout of prefabricated prestressed concrete beams was an early application of design optimization methodologies. However, most of the approaches found in the literature were not suitable to be implemented in real life bridge engineering. To fill the existing gap research has been conducted in past years by the authors to optimize prefabricated concrete beams formulating the problem in such a way that could be applied directly by bridge designers in beam and slab bridge decks. The software produced, labelled VTOP, contains the necessary capabilities for daily applications and possesses a user friendly graphical interface. This paper describes the problem formulation carried out and includes several examples to show the efficiency of the computer code implemented. Some of them are examples of single prefabricated concrete beams, and also an example showing the overall analysis of a bridge deck and the subsequent optimization of the prefabricated beam subjected to the internal forces produced by the external loading is included in the paper. 1 Beam and slab bridge decks Beam and slab decks are used for a wide variety of modern bridges. Many highway overpasses or urban bridges are designed with such arrangement. While the upper slab is always made in concrete, beams can be of steel or concrete. Also concrete beams can be prefabricated or built at the bridge site at the same time than slab producing a monolithic deck. But this latter technique, while sometime common in past times, is rarely used nowadays. Currently concrete beams are made in factories by means of a delicate mixture of cement and aggregates that produces a material with quite high strength to compressive stresses. The design is completed with prestressed steel tendons that translate

Keywords