| Near Surface Mounted (NSM) reinforcing method is a new form of strengthening with FRP materials for concrete structure. The NSM strengthening method, not only keeps the advantages of the externally bonded FRP laminate, but also offers additional practical improvements, such as simple construction process, good properties of flame resistance and abrasion proof, effective strengthening of the slab at negative moment area and full utilizing the high strength property of the FRP. In recent years, overseas researches and applications on NSM strengthening method are increasing. However, it is still in a starting-stage in China. This paper focuses on followed contents by performing test and analysis on interface bond while strengthening concrete structure by near-surface mounting CFRP plate strip.The paper analyzes tests for surface bonding properties between CFRP strip and concrete during the NSM strengthening course. It gives a detailed description on process and results for drawing tests of reinforced concrete structure with embedded FRP strip, as well sums up four typical failure modes. Depending on the outcomes of the trial, the paper reviews and analyzes the bonding length, slot size, bonding materials, concrete grades and other factors that affect its bonding properties.The paper analyzes the computing method for two characteristic values, namely bonding strengthτ_u and its corresponding slip value s_u, in the constitutive relation between interface bond stress and slip, during the course of mounting CRFP strip for strengthening concrete structure. It has also established a two-band bond-slip constitutive relation for the destructing interfaces of epoxy resin and epoxy mortar. By utilizing ANSYS common procedures for non-linear finite element analysis and in combinations of reasonable bond-slip constitutive relation and materials constitutive relation, it simulates the whole process of drawing test. The analysis results proved to coincide with the experimental results. |
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