Seismic capacity of unstrengthened and FRP strengthened masonry arches: tilting test and nonlinear numerical analysis

Cultural heritage preservation requires a deeper understanding of their seismic response and imposes the use of effective strengthening methods. Fibre-reinforced polymers (FRP) have emerged as an effective solution for strengthening masonry structural elements. The decision over the optimal configuration for a FRP-based strengthening is a trade-off between different objective functions such as strength, inelastic stiffness and cost. Although some studies have explored design alternatives and topology optimisation, experimental investigation remains limited, especially regarding the evaluation of seismic response. This study investigates the seismic capacity of unstrengthened and strengthened mortared–masonry arches through tilting table experiments and numerical simulations. The optimal strengthening arrangement is obtained through topology optimisation, and experimental results demonstrate its performance. A three-dimensional numerical model, following a macro-modelling approach through the so-called concrete damage plasticity material model, is adopted. Numerical results are validated with existing literature and experimental data. A parametric study is conducted for full-scale arches to evaluate the effect of dimensions and the embrace angle of masonry arches. The study reveals that the numerical model successfully replicates masonry arches' nonlinear behaviour and hinge mechanism. In addition, both experimental and numerical results highlight the effectiveness of optimised strengthening placement achieved through topology optimisation.