Strengthening of non-conforming RC shear walls using different steel configurations

Abstract The aim of the present paper is to examine the behavior of strengthened existing non-conforming reinforced concrete shear walls, namely shear walls which are designed and constructed according to older seismic codes non-compliant with modern earthquake design standards. A strengthening method using steel elements (straps and angles) is examined. For the purposes of the present study five shear walls – one reference and four strengthened – with shear ratio equal to 2.0, characterized as medium-rise, were designed and tested as cantilevers under static cyclic loading. The strengthened specimens included four different configurations, targeting each time to restrict the phenomenon of buckling of reinforcing bars under compression and control the cracking width along the web. The four strengthening configurations include only horizontal straps along the height, horizontal straps and corner angles along the height, horizontal straps and corner angles only in the lower part and, finally, combination of horizontal straps and corner angles in the lower part with bidiagonal (X shaped) configuration in the rest of the web.

[1]  T. Paulay,et al.  Seismic Design of Reinforced Concrete and Masonry Buildings , 1992 .

[2]  Michael N. Fardis,et al.  Deformations at flexural yielding of members with continuous or lap-spliced bars , 2010 .

[3]  A E Fiorato,et al.  Hysteretic Response of Reinforced Concrete Structural Walls , 1980 .

[4]  Emmanouil Vougioukas,et al.  Seismic assessment of existing RC shear walls non-compliant with current code provisions , 2013 .

[5]  W G Corley,et al.  WEB CRUSHING OF REINFORCED CONCRETE STRUCTURAL WALLS , 1984 .

[6]  Sinan Altin,et al.  Strengthening of RC walls using externally bonding of steel strips , 2013 .

[7]  Mjn Priestley,et al.  Ductility in Earthquake Resisting Squat Shearwalls , 1982 .

[8]  A. Kappos,et al.  Evaluation of hysteretic response and strength of repaired R/C walls strengthened with FRPs , 2007 .

[9]  Michel Bruneau,et al.  Seismic Retrofitting of Low-Rise Masonry and Concrete Walls Using Steel Strips , 2000 .

[10]  Mervyn J. Kowalsky,et al.  Improved Analytical Model for Shear Strength of CircularReinforced Concrete Columns in Seismic Regions , 2000 .

[11]  John B. Mander,et al.  Seismic Energy Based Fatigue Damage Analysis of Bridge Columns: Part 1 - Evaluation of Seismic Capacity , 1994 .

[12]  Michael E. Kreger,et al.  Rehabilitation of shear critical concrete columns by use of rectangular steel jackets , 1999 .

[13]  Mo Shing Cheung,et al.  Seismic Strengthening and Repair of Reinforced Concrete Shear Walls , 2000 .

[14]  Michael N. Fardis,et al.  Flexure-controlled ultimate deformations of members with continuous or lap-spliced bars , 2010 .

[15]  Gian Michele Calvi,et al.  Shear Strength of Reinforced Concrete Walls Subjected to Cyclic Loading , 2011 .

[16]  M. Fardis,et al.  Degradation of Shear Strength of Reinforced Concrete Members with Inelastic Cyclic Displacements , 2004 .

[17]  A. Kappos,et al.  Tests on Seismically Damaged Reinforced Concrete Walls Repaired and Strengthened Using Fiber-Reinforced Polymers , 2005 .

[18]  Pierino Lestuzzi,et al.  Static cyclic tests on lightly reinforced concrete shear walls , 2005 .

[19]  A E Fiorato,et al.  Behavior of Earthquake Resistant Structural Walls Before and After Repair , 1983 .

[20]  Amr S. Elnashai,et al.  Cyclic Behavior of RC Cantilever Walls, Part I: Experimental Results , 1995 .

[21]  A. Kappos,et al.  CYCLIC TESTS ON SEISMICALLY DAMAGED REINFORCED CONCRETE WALLS STRENGTHENED USING FIBER-REINFORCED POLYMER REINFORCEMENT , 2003 .

[22]  Koichi Maekawa,et al.  Path-dependent cyclic stress-strain relationship of reinforcing bar including buckling , 2002 .

[23]  Amr S. Elnashai,et al.  Cyclic Behavior of Reinforced Concrete Cantilever Walls, Part II: Discussions and Theoretical Comparisons , 1995 .

[24]  Michael D. Kotsovos,et al.  Behavior of Reinforced Concrete Structural Walls: Strength, Deformation Characteristics, and Failure Mechanism , 1990 .

[25]  Donald D. Magura,et al.  Strength of High-Rise Shear Walls - Rectangular Cross Section , 1972 .

[26]  Sinan Altin,et al.  Hysteretic behavior of RC shear walls strengthened with CFRP strips , 2013 .

[27]  R. Park,et al.  Flexural Members with Confined Concrete , 1971 .

[28]  Jun Shang Kuang,et al.  Seismic Behavior and Ductility of Squat Reinforced Concrete Shear Walls with Nonseismic Detailing , 2008 .

[29]  Henry G. Russell,et al.  Strength of Low-Rise Structural Walls , 1980 .

[30]  Rui Pinho,et al.  REPAIR AND RETROFITTING OF RC WALLS USING SELECTIVE TECHNIQUES , 1998 .