Design and evaluation of seismic strengthening techniques for reinforced concrete frames with soft ground story

Abstract This paper presents a design procedure and analytical evaluation of two strengthening techniques to improve the seismic performance of the existing non-ductile RC frames with soft-story at the ground story level. The first technique, termed as column retrofit (CR), uses only partial steel jacketing (or caging) to enhance the lateral strength and plastic rotational capacities of the deficient columns at the ground story level. The later technique, termed as full retrofit (FR), considers the aluminum shear links as supplemental energy dissipation devices in addition to the strengthened ground story columns. Steel collector beams and chevron braces are used to transfer the lateral load from the RC frame to these dissipating devices. Performance-based plastic design approach is used to proportion various elements of the strengthening techniques. Nonlinear static and dynamic analyses are carried out to evaluate the performance of the existing and the strengthened frames. The main parameters investigated are (a) interstory drift, (b) residual drift, (c) yield mechanism, (d) energy dissipation, and (e) lateral strength. The FR frame effectively controlled the drift response by avoiding the soft-story collapse because of the significant energy dissipation in the shear links. Moreover, the FR frame achieved the desired yield mechanism without exceeding the design target drift level.

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

[2]  G. De Matteis,et al.  Pure aluminium shear panels as dissipative devices in moment‐resisting steel frames , 2007 .

[3]  Murat Dicleli,et al.  Analytical study on seismic retrofitting of reinforced concrete buildings using steel braces with shear link , 2010 .

[4]  G. De Matteis,et al.  Low yield metal shear panels as an alternative for the seismic upgrading of concrete structures , 2007, Adv. Eng. Softw..

[5]  Federico M. Mazzolani,et al.  Pure aluminium: An innovative material for structural applications in seismic engineering , 2012 .

[6]  Durgesh C. Rai,et al.  Seismic testing of steel braced frames with aluminum shear yielding dampers , 2013 .

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

[8]  Mamoru Iwata,et al.  ENERGY DISSIPATION BEHAVIOUR OF SHEAR PANELS MADE OF LOW YIELD STEEL , 1994 .

[9]  W. J. Hall,et al.  Earthquake spectra and design , 1982 .

[10]  Subhash C. Goel,et al.  Performance-Based Plastic Design: Earthquake-Resistant Steel Structures , 2008 .

[11]  Subhash C. Goel,et al.  A seismic design method for steel concentric braced frames (CBF) for enhanced performance , 2006 .

[12]  Murat Dicleli,et al.  Efficient Energy Dissipating Steel-Braced Frame to Resist Seismic Loads , 2007 .

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

[14]  Subhash C. Goel,et al.  Performance-based plastic design of special truss moment frames , 2008 .

[15]  Dipti Ranjan Sahoo,et al.  PERFORMANCE-BASED PLASTIC DESIGN METHOD FOR BUCKLING RESTRAINED BRACED FRAMES , 2010 .

[16]  Durgesh C. Rai,et al.  Seismic strengthening of non-ductile reinforced concrete frames using aluminum shear links as energy-dissipation devices , 2010 .

[17]  Soon-Sik Lee.  Performance -based design of steel moment frames using target drift and yield mechanism. , 2002 .

[18]  Ian G. Buckle,et al.  Cyclic Behavior of Shear Links of Various Grades of Plate Steel , 2010 .

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

[20]  Federico M. Mazzolani,et al.  Numerical and experimental analysis of pure aluminium shear panels with welded stiffeners , 2008 .

[21]  Durgesh C. Rai,et al.  Seismic strengthening of RC columns using external steel cage , 2009 .

[22]  Božidar Stojadinović,et al.  Energy-based Seismic Design of Structures using Yield Mechanism and Target Drift , 2002 .

[23]  Wen-Cheng Liao,et al.  Performance-based plastic design of earthquake resistant reinforced concrete moment frames , 2010 .

[24]  Federico M. Mazzolani,et al.  An innovative methodology for seismic retrofitting of existing RC buildings by metal shear panels , 2009 .

[25]  Federico M. Mazzolani,et al.  Hysteretic behaviour of bracing‐type pure aluminium shear panels by experimental tests , 2011 .

[26]  Federico M. Mazzolani,et al.  Experimental tests on pure aluminium shear panels with welded stiffeners , 2008 .

[27]  Jeffrey W. Berman,et al.  Seismic behavior of code designed steel plate shear walls , 2011 .

[28]  Michael D. Engelhardt,et al.  Experimental Study of Local Buckling, Overstrength, and Fracture of Links in Eccentrically Braced Frames , 2005 .