Efficacy of FRP hooping in masonry domes: A simple numerical approach

A simple numerical approach to predict the efficacy of FRP hooping in historical masonry domes is presented. The dome is modeled with 8-noded elastic hexaedron elements connected by 1D trusses/springs on meridians and on parallels, where all the non-linearity takes place. The aim is to simulate the nonlinear behavior of domes through a FEM commercial software equipped only with non-linear 1D elements, namely point contacts and cutoff bars. The constitutive behavior of the trusses is assumed either perfectly brittle or perfectly ductile. A possible orthotropic behavior and the no-tension material case can be reproduced. An external retrofitting is simulated using trusses with an elastic-perfectly ductile behavior, assuming a perfect bond between substrate and reinforcement and imposing an ultimate strength for the trusses which takes into account in a conventional way the possible debonding/delamination from the substrate. The Italian code CNR DT200 and the existing specialized literature are used as reference. The models are benchmarked on a masonry dome reinforced with three hooping FRP strips and experimentally tested at the University Architecture Institute of Venice IUAV, Italy. The procedure is validated through extensive comparisons with available experimental data and numerical results obtained in the literature with a variety of different models. By the extensive comparisons carried out and discussed, the robustness and simplicity of the procedure are proven.