Structural Behavior of Strengthened RC Beams in Shear using CFRP Strips

Carbon fiber reinforced polymers (CFRP) were widely used in strengthening of reinforced concrete members in the last few years. Experimental and theoretical investigations were carried out to find the behavior of reinforced concrete beams strengthened in shear by CFRP strips. Six beams measured of 200x300x2000mm were investigated. The variables investigated in this work are orientation (vertical and inclined) and the spacing between CFRP strips. It was found that the strengthening by CFRP strips increased the crack, yield and ultimate load by 10%, 71% and 77% respectively on average. Inclined CFRP strips show a better performance than vertical CFRP strips with same distances and increase the yield and ultimate load by 11% and 13% respectively on average. By covering all faces of specimen with CFRP strips, the yield and ultimate load increased by 82% and 95% respectively. Using the CFRP strips changed the failure model from shear to flexural by increasing the shear strength, so the ductility was increased by 198% on average. CFRP increased the strain in compression face of concrete and the value was greater than (0.003). For all strengthened specimens, there was no effect on CFRP strips.

[2]  A. Al-Saidy,et al.  SHEAR BEHAVIOR OF URM RETROFITTED WITH FRP OVERLAYS , 1997 .

[3]  R. Santhakumar,et al.  Analysis of Retrofitted Reinforced Concrete Shear Beams using Carbon Fiber Composites , 2004 .

[4]  A. Nanni,et al.  Contribution of Externally Bonded FRP to Shear Capacity of RC Flexural Members , 1998 .

[5]  H. Saadatmanesh,et al.  Shear and Flexural Strengthening of R/C Beams with Carbon Fiber Sheets , 1997 .

[6]  D. Mertz,et al.  Shear Strengthening of Reinforced Concrete Beams Using Externally Applied Composite Fabrics , 1995 .

[7]  Omar Chaallal,et al.  Shear Strengthening of RC Beams with EB FRP: Influencing Factors and Conceptual Debonding Model , 2011 .

[8]  Don R. Alexander,et al.  Application of Artificial Neural Networks to Concrete Pavement Joint Evaluation , 1996 .

[9]  U. Meier,et al.  Strengthening of Structures with CFRP Laminates , 1991 .

[10]  M. Abdel-Jaber,et al.  Guidelines for Shear Strengthening of Beams Using Carbon Fibre-Reinforced Polymer (FRP) Plates , 2007 .

[11]  H. Saadatmanesh,et al.  RC Beams Strengthened with GFRP Plates. I: Experimental Study , 1991 .

[12]  Wang Wenwei,et al.  Experimental study and analysis of RC beams strengthened with CFRP laminates under sustaining load , 2006 .

[13]  Zhishen Wu,et al.  Short and long-term bond performance of prestressed FRP sheet anchorages , 2009 .

[14]  Abdalla Ab Sinusi Saiah,et al.  Use of Carbon Fiber Reinforced Polymer Laminate for strengthening reinforced concrete beams in shear : A review , 2013 .

[15]  Zhichao Zhang,et al.  Shear Strengthening of Reinforced Concrete Beams Using Carbon-Fiber-Reinforced Polymer Laminates , 2005 .

[16]  A Nanni,et al.  CONCRETE REPAIR WITH EXTERNALLY BONDED FRP REINFORCEMENT: EXAMPLES FROM JAPAN , 1995 .

[17]  Ian J Dussek,et al.  STRENGTHENING OF BRIDGE BEAMS AND SIMILAR STRUCTURES BY MEANS OF EPOXY-RESIN-BONDED EXTERNAL REINFORCEMENT , 1980 .

[18]  F Wayne Klaiber,et al.  Methods of Strengthening Existing Highway Bridges , 1987 .