Mechanical Response of Partially Prestressed Precast Concrete I-Beams after High-Range Cyclic Loading

Abstract

The variations of three residual mechanical parameters in a set of partially prestressed, precast concrete I-beams after being subjected to concentrated high-level cyclic loading are presented and discussed. These three mechanical parameters are flexural stiffness, natural frequency, and crack width. Two precast prestressed I-beams were tested under three-point bending cyclic loads, varying between 60 and 90% of their ultimate moment. This range corresponds to 72 and 108% of cracking moment. Having reached a prefixed number of cycles, the cyclic load testing stopped, and static testing was done up to 90% of the ultimate moment. Variations of the three aforementioned mechanical parameters with the number of cycles were observed, especially the crack width. The main conclusion, in this case, is that cyclic loading caused insignificant variations in beam stiffness and, as a consequence, insignificant variations in the mechanical parameters. On the contrary, significant variations in crack widths were observed.