Experiment and analysis on partial prestressed concrete continuous beams with unbonded CFRP tendon

9 two spams partially prestressed concrete continuous beams with unbonded CFRP tendon were fabricated，which were tested with two point load applied at each mid span. During the test，the mechanical behaviors at the stage of cracks，yielding of the non prestressed steel bar both in the critical section of intermediate support and mid span and ultimate limit state were investigated. The law of stress increment in the unbonded CFRP tendon was obtained in the design state and in the ultimate state. The calculation formula of equivalent length of equivalent plastic hinge zone of continuous beams is presented based on the test data for both states. The calculation formulas of the moment modification coefficient with the global reinforcement index of intermediate support as variable and with the plastic rotation of intermediate support as variable are presented respectively.