Experimental investigation on long-term behavior of prestressed concrete beams under coupled effect of sustained load and corrosion

Prestressed concrete beams are widely used in construction, while they may be attacked by the corrosion medium during the service. Past research works show that coupled effect of high stress and corrosion can significantly deteriorate the performance of prestressed concrete structures. This article presents an experimental investigation on long-term behavior of prestressed concrete beams under the coupled effect of sustained load and corrosion. During the accelerated corrosion process, six prestressed concrete beams were subjected to different levels of sustained loads, and time-dependent prestress loss and concrete stains were recorded and analyzed. It is observed that the local corrosion (i.e. pitting corrosion) of the steel strands was significantly affected by the sustained load level, and the coupled effect led to more serious damage on the beams than individual sustained load or corrosion. Bending loads were finally applied to investigate the influence of corrosion on flexural capacities of these beams. It was found that the flexural capacities and failure mode of the beams were significantly influenced by corrosion. Meanwhile, the corrosion has more significant effect on tension strength of strands rather than bond strength.