Comparative study of the seismic response of RC framed buildings retrofitted using modern techniques

The main purpose of this work is to compare different criteria for the seismic strengthening of RC framed buildings in order to find the optimal combinations of these retrofitting techniques. To this end, a numerical investigation is carried out with reference to the town hall of Spilinga (Italy), an RC framed structure with an L-shaped plan built at the beginning of the 1960s. Five structures are considered, derived from the first by incorporating: carbon fibre reinforced polymer (FRP)-wrapping of all columns; base- isolation, with high-damping-laminated-rubber bearings (HDLRBs); added damping, with hysteretic damped braces (HYDBs); FRP-wrapping of the first storey columns combined with base-isolation or added damping. A three-dimensional fibre model of the primary and retrofitted structures is considered; bilinear and trilinear laws idealize, respectively, the behaviour of the HYDB, providing that the buckling be prevented, and the FRP-wrapping, without resistance in compression, while the response of the HDLRB is simulated by using a viscoelastic linear model. The effectiveness of the retrofitting solutions is tested with nonlinear dynamic analyses based on biaxial accelerograms, whose response spectra match those in the Italian seismic code.

[1]  Gian Michele Calvi.  Choices and Criteria for Seismic Strengthening , 2013 .

[2]  Andrea Prota,et al.  Seismic behavior of a full-scale RC frame repaired using CFRP laminates , 2005 .

[3]  Stefano Sorace,et al.  Seismic Protection of Frame Structures by Fluid Viscous Damped Braces , 2008 .

[4]  Alessandro Baratta,et al.  Shaking Table Experimental Researches Aimed at the Protection ofStructures Subject to Dynamic Loading , 2012 .

[5]  Farzad Naeim,et al.  Design of seismic isolated structures : from theory to practice , 1999 .

[6]  Alessandro Baratta,et al.  FRP COMPOSITES RETROFITTING FOR PROTECTION OF MONUMENTAL AND ANCIENT CONSTRUCTIONS , 2012 .

[7]  Fabio Mazza,et al.  Control of the along-wind response of steel framed buildings by using viscoelastic or friction dampers , 2007 .

[8]  Dora Foti,et al.  Response of middle-rise steel frames with and without passive dampers to near-field ground motions , 2003 .

[9]  Giorgio Monti,et al.  Nonlinear Cyclic Behavior of Reinforcing Bars Including Buckling , 1992 .

[10]  Stephanie L. Walkup,et al.  Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete Structures (ACI 440.2R-02) , 2005 .

[11]  Fabio Mazza,et al.  Effects of near‐fault ground motions on the nonlinear dynamic response of base‐isolated r.c. framed buildings , 2012 .

[12]  Fabio Mazza,et al.  Design of Hysteretic Damped Braces to Improve the Seismic Performance of Steel and R.C. Framed Structures , 2014 .

[13]  I. Iervolino,et al.  Eurocode 8 Compliant Real Record Sets for Seismic Analysis of Structures , 2008 .

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

[15]  Amr S. Elnashai,et al.  Seismic retrofit schemes for RC structures and local‐global consequences , 2006 .

[16]  A. S. Elnashai,et al.  Confined concrete model under cyclic load , 1997 .

[17]  Seung-Eock Kim,et al.  Full-scale testing of space steel frame subjected to proportional loads , 2003 .

[18]  Vitelmo V. Bertero,et al.  Modeling of R/C Joints under Cyclic Excitations , 1983 .

[19]  Fabio Mazza,et al.  Nonlinear Dynamic Response of RC Buildings with Different Base Isolation Systems Subjected to Horizontal and Vertical Components of Near-Fault Ground Motions , 2012 .

[20]  Felice Carlo Ponzo,et al.  Jet-Pacs Project: Dynamic Experimental Tests and Numerical Results Obtained for a Steel Frame Equipped with Hysteretic Damped Chevron Braces , 2012 .

[21]  Fabio Mazza,et al.  Modelling and nonlinear static analysis of reinforced concrete framed buildings irregular in plan , 2014 .

[22]  Lorenza Petrini,et al.  A Critical Review of the R.C. Frame Existing Building Assessment Procedure According to Eurocode 8 and Italian Seismic Code , 2008 .

[23]  Fabio Mazza,et al.  Displacement‐Based Seismic Design Procedure for Framed Buildings with Dissipative Braces Part II: Numerical Results , 2008 .

[24]  Andrea Prota,et al.  Seismic strengthening of an under‐designed RC structure with FRP , 2008 .

[25]  Giuseppe Oliveto,et al.  Seismic retrofitting of reinforced concrete buildings using traditional and innovative techniques , 2005 .

[26]  Fabio Mazza,et al.  Displacement‐Based Seismic Design Procedure for Framed Buildings with Dissipative Braces Part I: Theoretical formulation , 2008 .

[27]  Fabio Mazza,et al.  Equivalent viscous damping for displacement-based seismic design of hysteretic damped braces for retrofitting framed buildings , 2014, Bulletin of Earthquake Engineering.