A Novel Technique of Seismic Strengthening of Nonductile RC Frame using Steel Caging and Aluminum Shear Yielding Damper

A novel strengthening scheme for seismically-weak RC frames is proposed which utilizes external steel caging to improve flexural/shear strength of columns and aluminum shear-yielding damper (Al-SYD) to further enhance lateral strength, stiffness and overall energy dissipation capacity of the frame. This paper describes the effectiveness of this scheme as evidenced in an experimental study on a reduced scale (1:2.5) single-story, single-bay, gravity-only designed reinforced concrete (RC) frame. The strengthened frame was simultaneously subjected to gravity loads and reversed cyclic lateral displacements as per ACI-374 loading protocol. An innovative connection scheme was designed to transfer a portion of frame lateral load to the energy dissipation device (Al-SYD). Besides the significant increase in lateral strength and stiffness of the strengthened frame, RC frame members did not suffer any major damage during the entire test protocol. This indicates significant reduction in force demand on existing RC members because of enhanced energy dissipation through hysteretic shear yielding of aluminum panels. Moreover, the simple connection scheme proposed in this study proved very efficient in transferring the frame lateral load to strengthening elements.

[1]  James O. Jirsa,et al.  LATERAL LOAD RESPONSE OF STRENGTHENED AND REPAIRED REINFORCED CONCRETE COLUMNS , 1988 .

[2]  J. Mander,et al.  Theoretical stress strain model for confined concrete , 1988 .

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

[4]  D. Rai,et al.  ALUMINIUM SHEAR-LINK FOR SEISMIC ENERGY DISSIPATION , 1999 .

[5]  Amr S. Elnashai,et al.  A novel technique for the retrofitting of reinforced concrete structures , 1995 .

[6]  Yeou-Fong Li,et al.  A constitutive model of concrete confined by steel reinforcements and steel jackets , 2005 .

[7]  Yan Xiao,et al.  SEISMIC RETROFIT OF RC CIRCULAR COLUMNS USING PREFABRICATED COMPOSITE JACKETING , 1997 .

[8]  F. Seible,et al.  SEISMIC RETROFIT OF CIRCULAR BRIDGE COLUMNS FOR ENHANCED FLEXURAL PERFORMANCE , 1991 .

[9]  Durgesh C. Rai,et al.  Postyield Cyclic Buckling Criteria for Aluminum Shear Panels , 2008 .

[10]  Durgesh C. Rai,et al.  ALUMINIUM SHEAR-LINKS FOR ENHANCED SEISMIC RESISTANCE , 1998 .

[11]  T. T. Soong,et al.  Seismic Design of Viscoelastic Dampers for Structural Applications , 1992 .

[12]  Stavroula J. Pantazopoulou,et al.  Experimental evaluation of FRP jackets in upgrading RC corroded columns with substandard detailing , 2004 .

[13]  Kenji Sakino,et al.  EXPERIMENTAL STUDIES ON CONCRETE FILLED SQUARE STEEL TUBULAR BEAM-COLUMNS SUBJECTED TO MONOTONIC SHEARING FORCE AND CONSTANT AXIAL FORCE , 1979 .

[14]  Abdullah,et al.  An investigation into the behavior and strength of reinforced concrete columns strengthened with ferrocement jackets , 2003 .

[15]  T. T. Soong,et al.  Passive Energy Dissipation Systems in Structural Engineering , 1997 .

[16]  R. Park,et al.  Seismic Load Tests on Reinforced Concrete Columns Strengthened by Jacketing , 1994 .