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