FLEXURAL STRENGTHENING OF RC COLUMNS WITH NSM FRP OR STAINLESS STEEL

The paper presents the results of a large-scale experimental program aiming to study the behavior of reinforced concrete (RC) columns under simulated seismic loading, strengthened in flexure (of crucial importance in capacity design) with different types and configurations of near-surface mounted (NSM) reinforcing materials. The role of different parameters is examined, by comparison of the lateral load versus displacement response characteristics (peak force, drift ratios, energy dissipation, stiffness). Those parameters were as follows: carbon or glass fiber-reinforced polymers (FRP) versus stainless steel; configuration and amount of NSM reinforcement; confinement via local jacketing; and type of bonding agent (epoxy resin or mortar). The results demonstrate that NSM FRP and stainless steel reinforcement is a viable solution towards enhancing the flexural resistance of reinforced concrete columns subjected to seismic loads. This is especially the case, when the retrofitting scheme combines epoxy-bonded NSM bars with local confining jackets (provided in this study with textile-reinforced mortars – TRM).

[1]  Laura De Lorenzis,et al.  Behavior and capacity of RC beams strengthened in shear with NSM FRP reinforcement , 2009 .

[2]  K. Borchert,et al.  A general bond stress slip relationship for NSM FRP strips , 2007 .

[3]  Joaquim A. O. Barros,et al.  Assessing the effectiveness of embedding CFRP laminates in the near surface for structural strengthening , 2006 .

[4]  J. Barros,et al.  NSM CFRP laminates for the shear strengthening of T section RC beams , 2006 .

[5]  Bo Wang,et al.  Debonding Failures of RC Beams Strengthened with Near Surface Mounted CFRP Strips , 2006 .

[6]  Deric J. Oehlers,et al.  Tests on the Ductility of Reinforced Concrete Beams Retrofitted with FRP and Steel Near-Surface Mounted Plates , 2006 .

[7]  Björn Täljsten,et al.  Concrete Beams Strengthened with Prestressed Near Surface Mounted CFRP , 2006 .

[8]  T. Triantafillou,et al.  Concrete Confinement with Textile-Reinforced Mortar Jackets , 2006 .

[9]  J. Barros,et al.  Bond Between Near-Surface Mounted Carbon-Fiber-Reinforced Polymer Laminate Strips and Concrete , 2004 .

[10]  S. Rizkalla,et al.  Bond Mechanism of Near-Surface-MountedFiber-Reinforced Polymer Bars for FlexuralStrengthening of Concrete Structures , 2004 .

[11]  S. Rizkalla,et al.  Near-Surface-Mounted Fiber-Reinforced Polymer Reinforcements for Flexural Strengthening of Concrete Structures , 2004 .

[12]  Joaquim A. O. Barros,et al.  Modeling of bond between near-surface mounted CFRP laminate strips and concrete , 2004 .

[13]  Laura De Lorenzis,et al.  Anchorage Length of Near-Surface Mounted Fiber-Reinforced Polymer Rods for Concrete Strengthening-Analytical Modeling , 2004 .

[14]  Karin Lundgren,et al.  Anchorage Length of Near-Surface Mounted Fiber-Reinforced Polymer Bars for Concrete Strengthening-Experimental Investigation and Numerical Modeling , 2004 .

[15]  Anders Carolin,et al.  Concrete Structures Strengthened with near Surface Mounted Reinforcement of CFRP , 2003 .

[16]  S. Rizkalla,et al.  INVESTIGATION OF BOND IN CONCRETE STRUCTURES STRENGTHENED WITH NEAR SURFACE MOUNTED CARBON FIBER REINFORCED POLYMER STRIPS , 2003 .

[17]  Antonio Nanni,et al.  Bond between Near-Surface Mounted Fiber-Reinforced Polymer Rods and Concrete in Structural Strengthening , 2002 .

[18]  Anders Carolin,et al.  Concrete beams strengthened with near surface mounted reinforcement of CFRP , 2001 .

[19]  Sami H. Rizkalla,et al.  Fiber Reinforced Polymer Reinforcement for Concrete Structures , 1999, SP-188: 4th Intl Symposium - Fiber Reinforced Polymer Reinforcement for Reinforced Concrete Structures.

[20]  S. O. Asplund.  Strengthening Bridge Slabs with Grouted Reinforcement , 1949 .