PSI - Issue 44

Francesco Morelli et al. / Procedia Structural Integrity 44 (2023) 574–581 Francesco Morelli, Agnese Natali, Gabriele Poggi / Structural Integrity Procedia 00 (2022) 000–000

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Caprili et al. 2022, Mattei et al. 2022), which design rules are discussed and defined by many reference codes (Braconi et al. 2015). As alternative solutions, Hybrid Coupled Shear Walls (HCSWs) are a structural seismic resistant system directly evolved from the Couple Shear Walls. Indeed, they are designed to exploit the same advantages of having two shear walls connected through coupling beams but trying to overcome the limitations associated with the limited dissipation capacity of reinforced concrete (r.c.) connecting beams and the necessity of having two concrete shear walls placed one close to the other. Fig. 1 schematically shows the distribution of the overturning moment in the case of uncoupled (Fig. 1a) and coupled (Fig. 1b) shear walls. In the former case, assuming a rigid floor, the overturning moment is distributed among the walls as a function of their relative stiffness whereas in the latter a part of the overturning moment is resisted by the formation of a couple of axial forces in the walls (T and C in Fig. 1b). The magnitude of these forces is strictly dependent on the shear and bending stiffness of the coupling beams. In both cases the base shear is divided between the two walls. a b

Fig. 1. Schematic representation of the overturing moment distributions in the case of (a) uncoupled shear walls; (b) coupled shear walls (Manfredi et al. 2015).

HCSWs are characterized by only one r.c. shear wall and by two steel side columns, connected through steel coupling beams, as showed in Fig. 2. The overall behavior is quite similar to the coupled shear walls, but the tension and compression forces, T and C of Fig. 1b, occur in the two steel side columns while the base shear is resisted by the r.c. wall only. Moreover, the steel coupling beams can be used as dissipative elements and the whole systems can be designed using a capacity design approach (Zona et al. 2016).

Fig. 2. Structural scheme of a HCSW (Manfredi et al. 2015).