Exploratory Experimental Study on Fatigue Prestress Loss of Prestressed Concrete Beams

To study the fatigue prestress loss of prestressed concrete beams, four bonded post-tensioned bonded concrete simple supported beams were designed and constructed for constant-amplitude fatigue load displacement tests. Strain sensors were embedded into the pre-pressed zone of the mid-span of the simply supported concrete test beams, and the fatigue prestress losses were calculated by strain increments in the concrete. The experimental results show that the phenomenon of fatigue prestress loss was present and primarily occurred in the forepart of cyclic fatigue test, and appeared to fit an exponential function law regarding cyclic fatigue load under dynamic loading for prestressed concrete beams. The preliminary results may be useful as a reference to improve the theory for designing prestressed concrete bridges.