Strengthening by Means of External Prestressing

Abstract

This paper deals with the behavior of reinforced concrete, partially prestressed concrete, and prestressed concrete beams, subjected to cyclic loading and then strengthened by means of external prestressing. The comparison between the experimental tests and the numerical analyses shows that the load-carrying capacity of the rehabilitated structure is greater than that of the old one plus the increase needed to cancel the bending moment decrease due to the external tendons. The prestressed concrete beam tested shows that stresses in the concrete exceed the stability limit, whereas the reinforcement does not yield. In spite of the considerable increase of its load-carrying capacity under monotonic loading, the efficiency of this beam, if subjected to a load history similar to that prior to strengthening, is doubtful.