VARIOUS FRP STRENGTHENING TECHNIQUES FOR RETROFITTING CONCRETE STRUCTURES

The need for repair and strengthening of deteriorated, damaged, and substandard infrastructure is a major challenge worldwide. The demand for increasingly heavier truck loads is forcing bridge owners to upgrade existing structures. In response to the growing need for concrete repair and rehabilitation, this paper describes an experimental program conducted to investigate the feasibility of using different strengthening techniques as well as different types of fiber reinforced polymer (FRP) in strengthening concrete members. Three half-scale models of a prestressed concrete bridge were constructed and tested to failure. Five strengthening techniques were studied. To evaluate bond characteristics of the most efficient techniques, a total of 24 concrete beams were constructed and tested under monotonic static loading. Design guidelines for the development length of near surface mounted CFRP bars, strips, and externally bonded CFRP sheets used in strengthening concrete beams are proposed. Ultimate capacity as well as failure mechanism of concrete beams strengthened with various FRP techniques are also presented.