PSI - Issue 44

Greta Agata Venneri et al. / Procedia Structural Integrity 44 (2023) 291–298 Greta Agata Venneri et al. / Structural Integrity Procedia 00 (2022) 000–000

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“Case study 2” is a three-storey building with rectangular plan of 20.5 m x 10.8 m made of six bays at 2.3 m÷3.5 m in the North-South direction and one bay with a span of 10 m in the East-West direction. The storey height is equal to 3.75 m, except for the first floor, which has a height of 2.4 m. Columns have a HE 240 A cross-section. The decks are made of clay blocks and RC joists. The primary girders are characterized by IPE 400 cross-section for the first and second floors and IPE 330 cross-section for the third floor; secondary beams are made of IPE 180 cross-section. The steel grade of members and plates is Fe 37 B. Beam-to-column joints are welded, column bases have stiffening plates welded to the column and to the base plate. Foundations are formed by RC beams. Classification through the Component Method (CEN 2005; D’Alessandro et al. 2018) of the examined joints revealed that all beam-to-column joints and column bases are semi-rigid and partial-strength, unlike the mentioned design assumptions.

Fig. 1. (a) 3D model of Case study 1; (b) Beam-to-column joint of Case study 1; (c) Column base of Case study 1.

Fig. 2. (a) 3D model of Case study 2; (b) Beam-to-column joint of Case study 2; (c) Column base of Case study 2.

3. N umerical models 3.1. Moment-Resisting Frame models

To reach the goals of the work, three-dimensional finite element models of the buildings were set up using the MIDAS Gen software (Midas GEN 2021). Beams and columns were modeled as one-dimensional linear elements. FEMA type plastic hinges (FEMA 273 1997) have been implemented to take into account the nonlinear behavior of the sections of these elements, also considering the detrimental effect of buckling phenomena. Therefore, bending and shear hinges were assigned at the ends and middle length of the elements, respectively. Floors were not modelled