Preliminary results of experimental investigation and modelling of strenghtened barrell vaults

Recent earthquakes showed that most existing structures are characterized by high seismic vulnerability. In particular, the observations of the damages have individuated in masonry arches and barrel vaults the most critical elements in the seismic vulnerability of existing structures. Therefore, the understanding of their seismic performance has become a crucial problem in the field of structural engineering. Their dynamic behavior is generally evaluated according to simplified methods or, as an alternative, to complex FEM analyses. However, a deep knowledge of their dynamic behavior is still lacking from an experimental point of view and, so far, only few experimental researches have been conducted. At this regard, shaking table tests have been performed to investigate the seismic behavior of a full scale masonry vault with abutments. The vault presents a segmental arch with a span of 298 cm, a rise of 114 cm and 116 cm depth. The vault is made of solid facing clay brick and pozzolanic masonry mortar. The use of composite materials has shown to be effective for these structures. In this background the experimental tests can provide an efficient contribution to the interpretation of the reinforcement effects. The present paper presents a comprehensive overview of the main results of the experimental tests. In particular, the experimental results of an innovative reinforced system coupled with other traditional strengthened systems are herein presented. The reinforcement technique is based on TRM system (Textile Reinforced Mortar). The effects have been investigated by using the shaking table tests, both before and after the TRM reinforcement application. The strengthening systems have been applied to a full-scale masonry vault typically used as roofs in religious buildings. After strengthening, the seismic behavior of the vault was significantly improved. Increasing the PGA, the instrumental response of the specimen started to change, however first visible damage occurred at an almost doubled PGA. The seismic capacity of the unreinforced specimen was more than doubled and the vulnerability moved from the curved element to the masonry abutments. Therefore, additional interventions should be eventually made on the lateral abutments. The strengthening strategy (combination of innovative and traditional systems) was effective in preventing failure of the masonry vault.