PSI - Issue 44

Ernesto Grande et al. / Procedia Structural Integrity 44 (2023) 582–589 Grande et al. / Structural Integrity Procedia 00 (2022) 000–000

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It consists of a two-story/one-bay RC frame belonging to an existing building designed in the 1970s, according to the design practice of the time, i.e. without considering those details devoted to improve seismic performances. The building was severely damaged during the “L'Aquila Earthquake” (on the 6th of April 2009) with damages mainly concentrated in the exterior beam-column joints, with large diagonal cracks representative of a typical joint shear failure. The RC building was classified as “unsafe” after the post-earthquake inspections carried out by the practitioners in compliance with the Italian standard code (NTC 2018). The 2D frame was already studied by Del Vecchio et al. (2016) since it was one of the most vulnerable parts of the entire building. The Authors implemented a 2D Finite Element model in order to perform nonlinear static analyses and investigate the influence of the joints deformation capacity on the overall seismic response of the frame. Figure 2 shows the geometry of the RC frame with the details of its members and the relative reinforcements. Both columns of the first floor have a cross-section of 300x600 mm 2 , while sections of the two columns of the second floor are 300x500 mm 2 . All the columns are reinforced with (3+3) ϕ 14 longitudinal steel rebars; 2 ϕ 14 intermediate rebars are also arranged. The two beams have a 300x500 mm 2 cross section: the beam at the first floor is reinforced with (3+3) ϕ 14 deformed steel rebars, while at the second floor 2 ϕ 14 + 2 ϕ 16 are arranged at the top side and 2 ϕ 14 at the bottom. The transverse reinforcement was designed to prevent the shear failure of both beams and columns: 8 mm diameter steel hoops, 200 mm spaced, are arranged in all members, while no stirrups are disposed in the panel zone.

Figure 2. Geometric configuration and structural details of the selected RC frame (dimensions in mm) (Del Vecchio et al. 2016).