Exploratory Experiment of Fatigue Prestress Loss of Prestressed Concrete Beam

In order to exploratory study the fatigue prestress loss of prestressed concrete beams,4 bonded post-tensioned bonded concrete simple supported beams were designed and made for test of constant-amplitude fatigue load of displacement.Strain sensors were embedded into the pre-pressed zone of the mid-span of prestressed simple supported concrete test beams,the fatigue prestress loss were calculated by the measured stain increment of the concrete.The experimental results show that(1) there will be the phemomenon of fatigue prestress loss of prestressed concrete beam under dynamic loading,which will occur in the initial stage under dynamic loading mostly;(2) there is an exponential relation between fatigue prestress loss and fatigue cycles.The result is helpful for improving the designing theory of prestressd concrete bridge.