PSI - Issue 78

Franco Braga et al. / Procedia Structural Integrity 78 (2026) 2176–2183

2180

4.2. Finite Element Model (FEM) To analyze the seismic behavior of the buildings, a finite element numerical model was implemented using the SAP2000 calculation code produced by CSI Inc. of Berkeley, California (U.S.); linear dynamic analyses with response spectrum were performed. The modeling was performed using frame-type finite elements (with 2 nodes and 6 degrees of freedom per node) for beams and columns, considering the decks as infinitely rigid in their own plane due to the presence of a 4 cm thick r.c. slab. a b

Fig. 4. FEM – a) axonometric view b) indication of the “orders” of the pillars

4.3. Materials The following materials were considered in the analyses: Material

Type

Concrete

C20/25

High bond Steel bars

Fe 50-2 (f yd = f yk /1.15 = 278.2 MPa

4.4. Load analysis The following vertical loads were considered for the structural analysis (in kN/m 2 ): Floor G1(kN/m 2 ) G2(kN/m 2 ) Q(kN/m 2 ) Roof 2.4 1.1 0.5 Attic 2.4 0.0 0.5 Typical floor slab 2.4 2.4 2.0

The buildings were then subjected to the seismic actions prescribed by the seismic code in force at the time of the collapse (NTC08) and subsequently the actions recorded by the AMTS accelerometer station during the event of August 24, 2016. To define the design spectra at the SLV, as defined by the NTC08, the following parameters were used: Location: Rieti, Amatrice; Latitude ED50 42.6276° (42° 37' 39''); Longitude ED50 13.296° (13° 17' 46''); Altitude above sea level 959.37 m. Use Class II, Structure Coefficient q=1.5, Soil Category = B, Topographic Category = T2 Vertical Seismicity: Not Applied To define the design spectra for the actions recorded during the August 24, 2016 earthquake, the pseudo acceleration spectra from the AMTS station recordings were scaled using a structure coefficient q=1.5. The following load combinations were implemented: • COMBINATIONS PRESCRIBED BY THE SEISMIC CODE IN FORCE AT THE TIME OF THE EVENT (NTC08) SLV1 = G + 0.3 Q + ESLV x + 0.3 ESLV y SLV2 = G + 0.3 Q + 0.3 ESLV x + ESLV y • COMBINATIONS RELATED TO THE EVENT REGISTERED ON 24.8.2016 AMTS1 = G + 0.3 Q + EAMTSx + 0.3 EAMTSy+ 0.3 EAMTSz AMTS2 = G + 0.3 Q + 0.3 EAMTSx + EAMTSy+ 0.3 EAMTSz AMTS3 = G + 0.3 Q + 0.3 EAMTSx + 0.3 EAMTSy+ EAMTSz, where ESLV x,y = seismic action in the x,y direction determined using the SLV design spectrum (q=1.5) defined by NTC08 and EAMTS x,y,z = seismic action in the x (North-South direction), y (East-West direction), z direction