【作者】 李泽民；

【导师】 朱海堂；

【作者基本信息】 郑州大学 ， 水工结构工程， 2019， 硕士

【摘要】 我国辽阔的海域面积蕴藏着丰富的自然资源,海洋开发已成为我国重要的战略目标之一。然而海工钢筋混凝土结构的耐久性问题日益凸显。基于FRP筋线弹性、轻质高强、耐腐蚀与钢纤维高强混凝土抗压与抗拉强度高、抗变形能力强、韧性好以及抗腐蚀性能优良的特点,将FRP筋与钢纤维高强混凝土结合,形成FRP筋钢纤维高强混凝土结构,以改善FRP筋与混凝土之间的粘结性能,降低FRP筋与混凝土在重复荷载下的粘结损伤,增大FRP筋混凝土结构构件的截面刚度,提高结构构件的承载力及其延性。将FRP筋钢纤维高强混凝土用于海工结构中,既可以从根本上解决传统钢筋混凝土结构的钢筋锈蚀问题,又可以改善结构受力性能,提高结构的安全性、适用性和耐久性。本文通过8根试验梁(其中7根为BFRP筋钢纤维高强混凝土梁,1根为钢筋钢纤维高强混凝土对比梁),研究了试件FRP筋配筋率、筋材种类、预裂受损程度对受模拟海水溶液侵蚀后FRP筋钢纤维高强混凝土梁在重复荷载作用下的破坏形式及特征、裂缝发展、滞回曲线、残余变形、骨架曲线、延性、刚度退化、强度衰减等受弯性能的影响。结果表明,海水侵蚀作用降低了BFRP筋的极限抗拉强度和弹性模量,在重复作用下,试件破坏模式均为BFRP筋拉断破坏。适当增大FRP筋配筋率可以提高试件在重复荷载作用下的极限承载力、截面刚度,延缓试件开裂,改善试件延性;而预裂受损程度对试件的受弯性能则有着明显的不利影响,受损程度越高,钢纤维的增强阻裂作用越弱,试件的极限承载力、截面刚度和延性越差;对比钢筋钢纤维高强混凝土梁,海水侵蚀后的BFRP筋钢纤维高强混凝土梁在重复荷载下表现出更好的适用性和耐久性。基于试验结果,建立了BFRP筋钢纤维高强混凝土梁在重复荷载下受弯承载力的计算模型,提出了海水侵蚀BFRP筋钢纤维高强混凝土梁在重复荷载下受弯承载力的计算方法。更多还原

【Abstract】 The vast sea area of China contains abundant natural resources,and marine development has become one of our important strategic objectives.However,the durability of reinforced concrete structures in the marine environment.has become increasingly prominent.Based on the characteristics of linear elasticity,light weight and high strength,corrosion resistance of FRP bars and high compressive and tensile strength,strong deformation resistance,good toughness and excellent corrosion resistance of steel fiber reinforced high-strength concrete,the FRP bars are combined with steel fiber reinforced high-strength concrete to form steel fiber-reinforced high-strength concrete beams reinforced with BFRP bars to improve the bonding performance and reduce the bond damage between FRP bars and concrete under repeated loading,increase the cross-section stiffness,and improve the bearing capacity and ductility of FRP bars reinforced concrete structures.The application of steel fiber-reinforced high-strength concrete beams reinforced with BFRP bars in the marine environment can not only fundamentally solve the problem of steel corrosion in traditional reinforced concrete structures,but also improve the mechanical properties of structures and enhance the safety,applicability and durability of concrete structures.In this paper,eight test beams(7 of them are steel fiber-reinforced high-strength concrete beams reinforced with BFRP bars and 1 of them is steel fiber reinforced high-strength concrete beams)are applied to study the effects of reinforcement ratio,damage degree and types of reinforcement on the failure modes,crack development,hysteresis curves,residual deformation,skeleton curves,ductility,stiffness degradation and strength attenuation of steel fiber-reinforced high-strength concrete beams reinforced with BFRP bars eroded by simulated seawater solution under repeated loading.The results indicate that the ultimate tensile strength and modulus of elasticity of BFRP tendons are reduced by seawater erosion.Under repeated loading,the failuremodes of the specimens are all BFRP bar rupture.Increasing the reinforcement ratio of FRP bars properly can increase the ultimate bearing capacity and section stiffness of specimens,delay the cracking of specimens and improve the ductility of specimens;however,the degree of damage has obvious adverse effects on the flexural performance of specimens.The higher the degree of damage is,the weaker the crack resistance of steel fibers,the worse the ultimate bearing capacity,section stiffness and ductility of specimens will be.Steel fiber-reinforced high-strength concrete beams reinforced with BFRP bars eroded by sea water show better applicability and durability under repeated loading compared with steel fiber-reinforced high-strength concrete beams reinforced with steel bars.Based on the test results,the calculation model of flexural capacity of Steel fiber-reinforced high-strength concrete beams reinforced with BFRP bars eroded by sea water under repeated loading is established,and the calculation method is proposed.更多还原