表层内嵌预应力螺旋肋钢丝加固混凝土梁变形性能理论分析

STUDY ON DEFORMABILITY OF CONCRETE BEAMS STRENGTHENED WITH PRESTRESSED MOUNTED HELICAL RIB STEEL WIRE NEAR SURFACE

课题组在对传统加固方法综合分析基础上,对既有工程结构提出了一种新型加固方法,即内嵌预应力螺旋肋钢丝加固法,并利用自行研发的预应力张锚系统,对内嵌预应力螺旋肋钢丝加固混凝土梁开展了静力加载试验研究。在试验研究基础上,该文对9根内嵌预应力螺旋肋钢丝加固梁不同受力阶段进行了深入理论分析,并基于一定的假设,给出了加固梁从预应力放张到破坏整个过程中不同受力阶段的弯矩-曲率计算公式,以此编制了荷载-挠度关系计算方法,利用相关计算公式对加固梁的开裂荷载、屈服荷载、极限荷载值及其对应的挠度值进行了理论计算、分析,并将计算结果与试验结果进行了对比,两者吻合较好。研究成果为该加固技术的实际工程应用提供了理论参考。

Based on the analysis of traditional reinforcement methods,a new reinforcement technology with prestressed helical rib steel wire bonded in sawed grooves in the concrete cover is presented.Nine concrete beams strengthened with mounted（NSM） prestressed helical rib steel wire near surface under static loads are tested using the tension and anchor prestressed system researched by author and her research team.Based on the experiment and some suppositions,the stress-states of the beams are further theoretically analyzed.The various types of failures and deformability of the strengthened beams were summarized,and the calculating formulas are proposed,including bending moment-curvature and load-flexibility of the strengthened beams in different stress-states.By using the formulas,the first-crack load,the steel-yielding load,the ultimate load and their corresponding deformation of the beams are calculated and analyzed.The formulas were validated by a good agreement between the analysis and the experimental results.The results may be a theoretical reference for practical engineering applications.