PSI - Issue 44

Alessandro Lubrano Lobianco et al. / Procedia Structural Integrity 44 (2023) 910–917 A. Lubrano Lobianco et al./ Structu al Integrity Procedia 00 (2022) 00 – 00

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Fig. 2 – a) Front view of the case study building and b) typical floor plant of the case study building

3 FE Model The FE model of the building was made in OpenSees (McKenna F. et al., 2000). Both column and beam elements are modelled by using nonlinearBeamColumn elements with a Hinge-Radau integration. The length of the plastic hinge, necessary to define the zone within which to concentrate the plasticity of the element, was defined in accordance with (Paulay, T., Priestley, 1992)0, considering the following relationship:

h

0.08 0.22 2 f d =  +   ym bar

L

2)

p

where h is the shear length of the element, f ym is the yield strength of the steel and d bar is the diameter of the reinforcement bars. Then, in the region defined as a plastic hinge, a fibre section with a patch square and a subdivision number equal to 30x30 was assigned for the concrete fibres, while a straight layer with a number of fibres equal to the reinforcing bars present in the cross-section was assigned for the steel fibres. The concrete fibres were assigned a constitutive law with the Concrete01 model whose parameters are 32 MPa for concrete compressive strength and elastic modulus of 31 GPa, while the steel was modelled with the Hysteretic model where the yielding point is 535 MPa in terms of strength and 0.0029 for strain (Del Vecchio et al., 2019). In the other part of the element, out of the plastic hinge length, an elastic section was assigned. The building is governed by a flexural failure mode; hence the shear behavior of the columns is not modelled. Time-history analysis Nonlinear dynamic analyses are performed through the time history recorded by the EST accelerometer station of L'Aquila in 2009 (AQG). The chosen time history has been appropriately scaled to simulate different damage scenarios. Starting from an intensity of 100%, defined as the original signal intensity, the time history has been scaled to 20%, 40%, 60% 80%, 125%, 150% and 200%. Each of these intensities, including the 100% intensity, were applied in the two directions of the structure according to the following loading patterns: • 1.00 X • 1.00 Z 4

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