PSI - Issue 78

Lorenzo Audisio et al. / Procedia Structural Integrity 78 (2026) 1277–1284

1282

4. Validation and Comparison with Numerical Models and Existing Formulations To validate the effectiveness of the proposed formulation for the dynamic amplification factor R, comparative analyses are conducted against results from numerical FEM simulations as well as alternative formulations documented in the scientific literature and existing design codes. A series of parametric analyses are carried out on building models with varying dynamic properties and number of stories, in order to evaluate the seismic response of acceleration-sensitive NSEs. For clarity and brevity, the results presented in this study refer to a representative case study: a four-story frame structure. In this model, developed using the OpenSeesPy environment, the NSE is modelled as a frame element rigidly connected to a specific floor, with a lumped mass applied at the free-end node. This modelling strategy enables a realistic simulation of the potential dynamic interaction between the primary structure and the NSE under seismic excitation.

Fig. 5. Comparison of FRS Models on a Four-Storey Structure

Figure 5 presents a comparative analysis between the results obtained from FEM simulations and several existing formulations for evaluating the FRS at different levels of a four-story structure. Specifically, the pseudo-acceleration values S a are plotted as a function of the natural period T a of the non-structural element (NSE), for each of the building’s four floors. The black curve represents the reference solution derived from the FEM model, in which the NSE is explicitly modeled using a frame element with a lumped mass. The remaining curves correspond to the results obtained using the following analytical formulations: • Proposed model (red), with fixed coefficients c=1 and e=0.45;