Anchorage and long-term losses of a prestressed externally bonded CFRP system

Prestressed externally bonded FRP systems provide a means of more efficiently utilizing FRP. Quantifying losses associated with prestressing anchorage and long-term behaviour, primarily associated with creep and relaxation, is critical to understanding the behaviour and to the design of such systems. This study describes the experimental assessment of initial losses associated with anchorage and long-term behaviour of a CFRP system that is post-tensioned, mechanically anchored and subsequently bonded to the tension face of reinforced concrete members. Both flexural tests of strengthened beams and tension relaxation tests of the CFRP system are presented. It is shown that the prestress losses of the CFRP post-tension system were mainly due to initial losses while the long-term prestress losses were dominated by CFRP relaxation and occurred primarily in the ten days following the prestressing operation.