【作者】 任振华；

【导师】 曾宪桃； 丁亚红；

【作者基本信息】 河南理工大学 ， 工程力学， 2009， 硕士

【摘要】 既有建筑结构、桥梁结构的维修与加固是世界各国都普遍关注的重大科研课题。近年来,由于纤维增强复合材料(FRP)具有质量轻、耐腐蚀、强度高等优点,被广泛应用于混凝土结构维修加固工程中,但价格相对较昂贵。据国内资料显示,螺旋肋钢筋的强度高、延性好、锚固性能优良、价格低廉,是高效加固混凝土构件的理想材料。本文从介绍钢筋混凝土结构维修加固及科学研究现状出发,探讨了纤维增强复合材料及螺旋肋钢筋加固钢筋混凝土结构的技术优势和不足,对内嵌螺旋肋钢筋和CFRP筋加固混凝土梁的静载特性进行试验研究的基础上,提出了对螺旋肋钢筋施加预应力,将非预应力碳纤维筋和预应力螺旋肋钢筋一并嵌入到混凝土梁预先开好的槽道内,并对复合加固后混凝土梁进行静载特性研究。对内嵌螺旋肋钢筋加固混凝土梁进行静载特性的试验研究,采用了4根混凝土梁,其中一根为对比梁,另外3根用内嵌螺旋肋钢筋进行加固;对内嵌CFRP筋加固混凝土梁进行静载特性的试验研究,也采用了4根混凝土梁,其中1根为对比梁,另外3根用内嵌CFRP筋进行加固;对CFRP筋—预应力螺旋肋钢筋加固混凝土梁进行静载特性的试验研究,采用了7根混凝土梁,其中1根混凝土梁为对比梁,3根编号为BF2P1的混凝土梁,在每根梁上所开的槽道内,对称嵌入2根非预应力CFRP筋,中心线槽道内嵌入1根预应力螺旋肋钢筋,其预应力水平分别取其抗拉强度的30%、45%和60%;3根编号为BF1P2的混凝土梁,在中心线位置上嵌入1根非预应力CFRP筋,两边的槽道内嵌入2根预应力螺旋钢肋筋,其预应力水平分别取其抗拉强度的30%、45%和60%。研究表明:内嵌螺旋肋钢筋加固的混凝土梁能显著提高混凝土梁的抗弯能力和变形刚度,是一种非常有效的加固方法,依据嵌入加固材料螺旋肋钢筋的数量不同,其极限承载力的提高幅度达到20.91%～90.91%;同样,内嵌CFRP筋加固的混凝土梁也能显著改善混凝土梁的工作性能及极限承载能力,依据加固量的不同,加固后混凝土梁的极限承载能力提高幅度在70.91%～116.36%之间;而内嵌CFRP筋—预应力螺旋肋钢筋复合加固的混凝土梁,能显著提高混凝土梁的抗弯能力及弯曲刚度,与前二者相比更为有效,其极限承载能力提高幅度更大。在对内嵌CFRP筋—预应力螺旋肋钢筋加固混凝土梁试验研究基础上,结合现行规范及基本假设,对CFRP筋及预应力螺旋肋钢筋复合加固的混凝土梁不同的破坏模式进行了系统分析,并根据具体情况分析了螺旋肋钢筋施加预应力不同阶段的受力情况及预应力损失情况,导出了不同破坏模式下,加固混凝土梁极限承载力的理论计算公式。更多还原

【Abstract】 The repair and reinforcement of existing building structure,bridge structure is a significant scientific research item with interest by every country all over the world.In recent years,the Fiber Reinforced Plastic has been widely applied in repairing and strengthening concrete structure with its lightweight,corrosion resistance and high strength,but the price of FRP is relatively expensive.According to the domestic information,the Helical Rib Rebar with its high strength,good ductility,nice anchoring performance and lower price is a ideal material used to strengthen concrete component.This thesis discusses the technical superiority and inadequate of using CFRP or HRR to strengthen the concrete structure from the present situation of concrete structure repairing and strengthening,puts forward to a new strengthening method and study the static behaviors of beams strengthened with NSM CFRP and prestressed HRR based on researching the static behaviors of RC beams strengthened with HRR and CFRP,respectively.Four concrete beams ,one is comparison beam that was not strengthened and other three beams that were strengthened with NSM HRR,are tested to research the static performances,and the other four beams,one is comparison beam and the other three beams were strengthened with NSM CFRP,were tested to study the static performance of the beams.The static behaviors of seven reinforced concrete beams strengthened with NSM CFRP and prestressed HRR were emphatically researched in this thesis. one of the beam is comparison beam,there are three beams that the number is BF2P1,each beam was cut three grooves in concrete protect layer that two CFRP rebars and one prestressed HRR were put into the groove which the level of the prestress were 30%,45%,60% of HRR strength, espectivelly,there are three beams that the number is BF1P2,each beam was cut three grooves in concrete protect layer that one CFRP rebar and two prestressed HRR were put into the groove which the level of the prestress were 30%,45%,60% of the HRR strength.The results of the experiment indicates that,the reinforced concrete beam strengthened with NSM HRR is a effective strengthening method that can effectively enhance the bending capacity and destroy stiffness and the limit bearing capacity of the beam has increased from 20.91% to 90.91% compared with the comparison beam. Similarly,the reinforced concrete beam strengthened with NSM CFRP can effectively improve the working function and enhance limit bearing capacity increasing from 70.91% to 116.36% compared with the comparison beam,the reinforced concrete beam strengthened with NSM CFRP rebar and prestressed HRR can effectively improve the operating performance and bending stiffness,the method of reinforced concrete beams strengthened with NSM CFRP and prestressed HRR is better than that of the reinforced concrete beam strengthened with single material,which can highly improve the first-crack load,ultimate load,the strengthening concrete beam of BF2P1 is better than BF1P2.The different destroy forms and bearing-capacity of the beam strengthened with NSM CFRP and prestressed HRR has been analysed based on the experiment and the fundamental assumption,and forcing and prestress lose of HRR were analysed in different phase and the theory formula of limit bearing capacity of the beam strengthened has been deduced in different destroy forms.更多还原