Numerical modeling of the out-of-plane dynamic response of masonry gable walls via a high-fidelity block-based finite element modeling approach – part I

Abstract

This paper deals with the blind prediction of the dynamic out-of-plane (OOP) response of unreinforced masonry gables via block-based modelling within a competition organized by ERIES SUPREME. Three gable wall specimens were tested at the EUCENTRE foundation in Pavia, Italy, under incremental shaking-table earthquake loading until collapse. In the tests, each wall was subjected to distinct boundary conditions, simulating interactions with stiff, flexible, and semi-flexible diaphragms. The competition challenged participants to predict the responses of two of these walls, replicating stiff and flexible diaphragms, with minimal access to experimental data and outcomes, emphasizing the need for reliable modeling techniques. The authors utilize a novel 3D block-based model, originally developed for cyclic quasi-static responses and recently extended to dynamic one- and two-way OOP bending. Both the walls and the loading set-up are simulated. The masonry assembly of the walls is conceived as solid expanded blocks connected via zero-thickness planar joints in the former. The robustness of the predictions is enhanced through a sensitivity analysis exploring the influence of variations in mechanical properties, vertical and dynamic loading assumptions, and damping on the response. Numerical models predict the key experimental observations, such as the collapse onset, failure mechanisms, displacement demands, and dynamic responses, with good accuracy, achieving the best blind prediction results. Indeed, the modeling approach shows great capability to capture complex dynamic interactions, highlighting its potential in complementing physical testing. Moreover, the simulation is able to successfully predict not only the global response of the gables, but also to reproduce several details affected by the test set-up and loading assumptions. The modeling strategy appears a good candidate for sensitivity and probabilistic analysis, capable of extending the current understanding of seismic performance in masonry structures and overcoming limitations inherent in experimental methods.