Upper bound limit analysis model for FRP-reinforced masonry curved structures. Part II : structural analysis

A homogenized full 3D limit analysis model for the evaluation of collapse loads of FRP-reinforced masonry vaults is presented. Six-noded rigid infinitely resistant wedges are used to model masonry. Three-noded rigid infinitely resistant triangles are used to model FRP strips. Plastic dissipation is allowed only at the interfaces between adjoining elements. Unreinforced masonry homogenized failure surfaces obtained in Part I of the present paper are used to evaluate plastic dissipation at the interfaces between masonry/masonry elements. A possible dissipation at the interfaces between FRP triangles and masonry wedges is also considered in order to take into account, in an approximate but effective way, the possible delamination of the strips from the supports. Italian code CNR DT 200 [CNR-DT 200, 2006. Guide for the design and construction of externally bonded FRP systems for strengthening existing structures. C.N.R., National Research Council, Italy; 2006.] formulas are used to evaluate peak interface tangential strength. While the delamination from the support can be modelled only in an approximate way within limit analysis, the aim of the paper is to accurately reproduce the change in the failure mechanism observed in experimentations due to the introduction of strengthening elements