无粘结CFRP筋部分预应力混凝土连续梁试验与分析

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

制备了9根两跨无粘结CFRP筋部分预应力混凝土连续梁,并完成了每跨三分点加载试验。考察了在加载过程中的开裂、中支座控制截面非预应力筋屈服、跨中控制截面非预应力筋屈服、极限破坏状态等阶段的受力特征,获得了无粘结CFRP筋在设计用承载能力极限状态和真实承载能力极限状态下的应力增长规律,基于试验结果提出了在这两个状态下的中支座两侧等效塑性铰长度计算公式,提出了分别以中支座控制截面综合配筋指标为自变量和以中支座控制截面相对塑性转角为自变量的弯矩调幅的计算公式。

9 two spans 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 seetion 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.