Numerical simulation of shaking table tests on two modern URM buildings using equivalent-frame modeling

This paper presents the results of the numerical analyses conducted to reproduce the shake table tests performed in Lisboa at the LNEC laboratory (Laboratório Nacional de Engenharia Civil) on two full-scale masonry prototypes. The equivalent frame modeling strategy was chosen as an effective compromise between computational efficiency and accuracy in simulating the seismic behavior. The model was developed using a blind prediction approach, like that typically employed by practitioners in seismic assessments of existing buildings. Based on geometry and construction details, appropriate modeling strategies were implemented to capture the nonlinear behavior of structural elements. A piecewise-linear constitutive law was applied and, as a novel contribution, the flange effect was incorporated using an equivalent beam, calibrated with a practice-oriented analytical expression that accounts for geometry and material characteristics of the web and flange. Experimental data from panels with similar masonry were used to calibrate the strength parameters at the structural element scale. Another relevant contribution was the validation of EF models in predicting the seismic response of modern masonry typologies with box-like behavior under increasing levels of nonlinearity and structural irregularity in the two prototypes. To this aim, nonlinear dynamic simulations replicating the shaking table tests were performed and compared with the experimental results. Traditional techniques were combined with more innovative tools to manage the large volume of experimental data and gain insights into the prototypes’ response. The numerical analyses successfully reproduced the experimental behavior across the full set of data and for both models, without the need for further refinement.