Moment Capacity Charts for Strengthening of RC Beams With Near Surface Mounted FRP Reinforcement

Volume 18 , Issue 2 , February 2016 , Pages 365-378

Authors

¹ Departement of Civil Engineerng, Faculty of Engineering, University of Sulaimani,

Near surface- mounted fibre reinforced polymer is a new technique for strengthening

structural members beside externally applied fibre reinforced polymer (FRP) technology.

In NSM technique, the FRP material is applied to the tension region of the member inside

pre-prepared grooves. In externally applied FRP the debonding of the fibres is a major

issue thus, the full utilisation of FRP material can not be achieved, and the fibres are more

susceptible to environmental effects. With NSM FRP, these issues can be controlled more

effectively. ACI Committee 440 [1] has presented guidelines for design and construction

of externally FRP method for strengthening of concrete structures. Although many

experiments have been conducted on NSM FRP in flexure strengthening of RC beams,

no code is introduced yet. Theoretical studies to derive equations for calculating moment

capacity of strengthened beams have been introduced but mostly require several trial

procedures to reach the required effective strain for FRP. In this study, a moment

capacity chart is introduced based on several assumptions in the derivation of flexure

capacity equation. To avoid the brittle behaviour of FRP, it is suggested that the

utilization of FRP to be limited to 70% of its ultimate capacity for CFRP, and an

equivalent area of reinforcement is adopted for simplicity. Experimental results of other

researchers have been verified with the proposed charts, and a good comparison of results

have being achieved.

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