预应力AFRP筋混凝土构件抗弯性能研究

摘要

Based on plane section assumption and section internal force equilibrium,the formulas for calculating the flexural capacity and the crack moment of the cross sections of reinforced concrete members with prestressed AFRP(Aramid Fiber Reinforced Plastic) bars were deduced.The flexural behavior of 5 sets of test specimens of reinforced concrete members with prestressed AFRP bars with the same overall reinforcement ratio and different initial tension control stress were compared.The results show that the formulas well describe the stress characteristics of the specimens.The tension control stresses of AFRP bars have little influence on the ultimate flexural capacity of the specimens.The increase of tension control stress can effectively improve the crack resistance bearing capacity of the specimen.When the tension stress is close to the 25% of the AFRP bar ultimate tensile strength,the crack resistance bearing capacity can increase 77.65%,then effectively delaying the section cracking time and improving the structure flexural rigidity.%基于平截面假定和截面内力平衡条件,推导了预应力AFRP(一种纤维增强复合材料)筋混凝土构件正截面受弯承载力及截面开裂弯矩计算公式,并对5组具有相同整体配筋率、不同初始张拉控制应力的AFRP筋混凝土构件的抗弯性能进行了对比.研究结果表明:提出的预应力AFRP筋混凝土构件抗弯承载力及开裂弯矩计算公式可有效描述该构件的受力特征;AFRP筋的张拉控制应力对AFRP筋混凝土构件极限抗弯承载力影响较小;而张拉控制应力的增大可有效提高AFRP筋混凝土构件的抗裂承载能力;当张拉控制应力接近于预应力AFRP筋极限抗拉强度的25%时,构件抗裂承载力相应提升77.65%,有效地延迟了截面裂缝开裂的时间,提高了结构的抗弯刚度.