Author(s)

C. Vázquez-Herrero & F. Martínez-Abella

Abstract

As is well known, prefabrication procedures allow significant reductions in construction time. In many countries, precast concrete bridges are customary and made up of pretensioned prestressed girders. Both the compressive and tensile strength of the concrete mix must be enough at transfer (which takes place typically two or three days after concrete casting) in order to avoid excessive prestress losses, and undesirable cracking. Many attempts have been made to increase the spectrum of the usual high performance concretes to other concrete types (i.e. normal strength concrete, lightweight concrete and recycled aggregate concrete). Why are these special concrete types not used in the current production of large pretensioned concrete girders? Technical problems have been observed at the critical zones: development length, geometrical discontinuities, supports, etc. A new technique has been developed by the authors to produce hybrid pretensioned concrete elements, combining the usual high strength concretes in the critical zones with other concrete types in the rest of the elements. Keywords: prestressed concrete, precast concrete, pre-tensioning, pretensioned, pretensioned, high performance, high strength, prestressed, girders, beams. 1 Introduction As is well known, the prefabrication procedures allow significant reductions in the construction time. In many countries precast concrete bridges are customary, made up of pretensioned prestressed girders deck.

Keywords

prestressed concrete, precast concrete, pre-tensioning, pretensioned, pretensioned, high performance, high strength, prestressed, girders, beams.