Influence of the frp strengthening, the shape and the movement of abutments on the collapse of arch stone bridges

The ultimate failure load of stone arch bridges is calculated in this paper by using finite element analysis. Contact interfaces simulating potential cracks are considered. Opening or sliding of a number of the potential interfaces indicates crack initiation [

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]. Fiber Reinforced Plastic (FRP) strips are then applied to the stone bridge and the ultimate load is recalculated. The failure modes of the reinforced arch are compared well with the ones received from relevant experiments published in the literature. The analysis of the unreinforced arch shows that, under the most critical quarter span loading, a four - hinges collapse mechanism arises. The occurrence of this type of collapse is indicated in the classical work of Heyman [

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] and has been observed in experiments. Three types of FRP reinforcement are applied in the arch. In particular, FRP is attached to the whole extrados, to the whole intrados and both to the extrados and the intrados of the arch. A cap model is used in order to model the failure of the masonry due to compression, while a v. Mises yield criterion is used for the FRP yielding. The possible failure modes of the reinforced structure are sliding of the masonry, crushing, debonding of the reinforcement and FRP rupture. Identical failure modes arise from the computer simulation and from experiments on reinforced arches published in the literature. A parametric investigation of the influence of the geometry of the unreinforced stone arch on the mechanical behavior of the structure is briefly described. Finally the effect of support settlement (vertical or horizontal movement) on the limit behavior is investigated. Common remarks with Heyman’s work arise. Further results and more details on the theory and the algorithms are given in the PhD Thesis of the first author [

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].