Behavior of reinforced concrete beams strengthened using CFRP sheets with innovative anchorage devices

The objective of this experimental study is to assess the effect of new flexural anchorage devices on improving the performance of strengthened reinforced concrete beams in flexure. Six reinforced concrete (RC) beams were prepared and tested, three of which having identical T cross-section and the other three with identical rectangular section. The first specimen in each series was tested as a control beam. The second specimen in each series was strengthened using four layers of flexural CFRP in addition to side GFRP bars. The sidebars were inserted longitudinally into side grooves at the level of primary steel reinforcement to prevent peeling off from the sides. The last specimen in each series was strengthened in flexure using identical four layers of CFRP plus GFRP patches installed longitudinally along both sides of the beam. The beams were tested under four-point bending until failure and the results for each series are evaluated. In addition, the outcome is compared with U-wrap anchorage technique that has been examined by others. It was concluded that using CFRP sheets with both anchorage devices significantly increased the flexural capacity beyond that of unanchored and U-wrap anchored specimens. Quantitatively speaking, T beams anchored with GFRP sidebars and GFRP side patches showed 74% and 58% increase in strength over unanchored strengthened specimens respectively.