FRP管混凝土组合结构理论研究

运用层板理论、平截面假定和平衡条件对FRP管混凝土梁柱构件进行了理论计算,分析了轴压比、径厚比、混凝土强度、配筋率和铺层角度对弯矩-曲率曲线的影响以及FRP配置率与弯矩-轴力相关曲线关系.部分理论分析与试验结果作了比较,弯矩-曲率曲线吻合较好.计算表明,FRP管混凝土组合结构能有效地提高构件的承载力,并由于FRP管的约束作用而提高混凝土强度和延性;弯矩-曲率曲线为双线性,第一刚度取决于混凝土刚度,第二刚度取决于FRP壳体刚度;当径厚比较小时轴压比对弯矩-曲率曲线影响较小,当径厚比较大时,随着轴压比增加,弯矩和极限曲率先增后减;配筋率增加则极限弯矩提高,耗能能力增加;随着纤维与杆件纵轴的角度减小,第二刚度和极限弯矩提高.

THEORETICAL STUDY ON CONCRETE -FILLED FRP TUBE COMPOSITE STRUCTURE

Based on the laminate theory,plane section assumption and equilibrium of internal force,a theoretical analysis was carried out for the beam-column members.The different parameters such as the ratio of a xial force to compressive capacity,strength of concrete,ratio of reinforcement,ratio of diameter to thickness of FRP jack and orientation of the fiber were co nsidered with respect to the effect on curves of moment-curvature and moment-thrust interaction diagrams.A part of the theoretical values was compared with experimental results.A good agreement was shown in the curves of moment-curvature.The theoretical calculation presents that concrete-filled FRP tubes can significantly improve the ultimate capability of members.In addition,because of the confining of FRP jack ,were not only strength but also ductility enhanced.The relationship of moment-curvature has two-linear behavior.The first slope depends on the stiffness of concrete and the second slope on FRP jack.It is evident that the ratio of axial force to compressive capacity has no effect on curves of moment-curvature if the ratio of diameter to thickness of FRP jack is low.Contrarily,as the ratio of axial force to compressive capacity increases,the moment and ultimate curvature improve greatly if the ratio of diameter to thickness of FRP jack is high.Increasing the ratio of reinforcement has effect on the curve of moment-curvature.As the angle with respect to longitudinal axis decreases,the second slope and ultimate moment increase greatly.