EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS Earthquake Engng Struct. Dyn. 2009; 38:61–78 Published online 5 August 2008 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/eqe.841 An innovative methodology for seismic retrofitting of existing RC buildings by metal shear panels G. De Matteis 1, ∗, † , A. Formisano 2 and F. M. Mazzolani 2 1 Department of Design, Rehabilitation and Control of Architectonic Structures, University of Chieti/Pescara ‘G. D’Annunzio’, Pescara, Italy 2 Department of Structural Engineering, University of Naples ‘Federico II’, Naples, Italy SUMMARY In the present paper, the seismic upgrading of existing reinforced concrete (RC) structures by means of steel and pure aluminium shear panels is examined. After a preliminary experimental evaluation of the performance of the bare RC structure, a design approach based on the capacity spectrum method has been developed according to the procedure provided in the ATC 40 American guidelines. First, the geometrical configuration of the applied shear panels has been defined according to simplified analytical relationships, while appropriate steel members have been designed to allow the insertion of shear panels in the existing RC structure. Then, complex finite element models have been implemented in order to check the reliability of the proposed design procedure. Also, a numerical evaluation of the global response of the upgraded structure has been processed aiming at evaluating the interaction between the RC structure and the metal devices. Finally, the effectiveness of the applied shear panels has been proven by means of full-scale experimental tests, which confirmed the significant improvement of the RC structure performance, in terms of strength, stiffness and deformation capacity. Copyright 2008 John Wiley & Sons, Ltd. Received 4 December 2007; Revised 23 June 2008; Accepted 25 June 2008 KEY WORDS: seismic retrofitting; RC buildings; metal shear panels; performance-based seismic design; FEM model 1. INTRODUCTION The seismic upgrading of existing reinforced concrete (RC) buildings represents an important issue for structural engineers, who are requested to find innovative structural solutions compatible with the existing structure but also to increase the performance of the buildings in case of seismic events. In fact, recent earthquakes showed that many RC structures are particularly vulnerable to the ∗ Correspondence to: G. De Matteis, Department of Design, Rehabilitation and Control of Architectonic Structures, University of Chieti/Pescara ‘G. D’Annunzio’, Pescara, Italy. † E-mail: demattei@unina.it Copyright 2008 John Wiley & Sons, Ltd.