Issue 48

M. L. Puppio et alii, Frattura ed Integrità Strutturale, 48 (2019) 706-739; DOI: 10.3221/IGF-ESIS.48.66 706 Design of Civil Environmental Engineering Parametric analysis on external dissipative link system for seismic protection of low rise R.C. buildings Mario Lucio Puppio, Martina Ferrini University of Pisa, Italy mariolucio.puppio@ing.unipi.it, martina.ferrini90@gmail.com A BSTRACT . The seismic rehabilitation of existing R.C. and masonry buildings is a topical issue in Civil Engineering. A useful technique consists in the introduction of the external bracing system. This kind of intervention can be improved through the introduction of dissipative links, investigated here with the help of some examples. The links are made of common steel profiles: length, geometry and positioning are considered as design parameters. A general procedure of link-bracing optimization is proposed by applying a set of identical external restraints. The adopted dissipative links allow a cheaper and more effective design both in terms of ULS and of DLS: the damages are addressed in a small area allowing easy replacement of the links in case of an earthquake. K EYWORDS . Seismic rehabilitation; Existing buildings; External bracing systems; Dissipative links; Structural optimization. Citation: Puppio, M. L.., Ferrini, M., Parametric analysis on external dissipative link system for seismic protection of low rise R.C. buildings, Frattura ed Integrità Strutturale, 48 (2019) 706-739. Received: 31.01.2019 Accepted: 06.02.2019 Published: 01.04.2019 Copyright: © 2019 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION AND STATE OF THE ART External retrofit with bracing systems he seismic enhancement of existing Reinforced Concrete (R.C.) structures, built before the introduction of seismic regulations, is a topical issue [1–3]. In recent years several researches have been carried out on this topic to study the behaviour of the external seismic consolidation systems. In this sense, structural irregularity has a relevant role. In fact, structural response is significantly affected by geometric and material irregularity [4,5]. A relevant intervention should consider mechanical irregularity, particularly the high dispersion in concrete resistance [6]. The design of a new external bracing structure can satisfy this requirement [7]. Another critical issue is the respect of different aspects covered by technical norms, such as energy efficiency [8], fire protection [9] or the use of isolation systems. The optimization of the refurbishment of external walls or facades in terms of energy efficiency [a] or fire protection [b] or the design of seismic isolators [c] can modify the choices with the aim of minimizing the impact or the costs of intervention. T