Plywood extrados retaining structures for the retrofit of single-leaf vaults
Single-leaf vaults are acknowledged as particularly vulnerable to seismic actions: remarkable damages and collapses were surveyed on these elements after earthquakes, regardless of the earthquake intensity and of the level of the structure global damage. This chapter discusses the seismic vulnerability of single-leaf vaults, and presents a new strengthening technique for the reduction of the seismic vulnerability of single-leaf vaults. Extrados lightweight plywood centerings applying passive confinement are conceived to delay the onset of the vault failure mechanism. The efficiency of the strengthening is assessed through comparison with the seismic response of a reference unreinforced single leaf vault. Single leaf vaults are thin vaults made of a single layer of bricks laid flat, wide spread over the European territory. In thinner vaults the ideal resisting arch has reduced possibility to shift and modify within the small vault thickness to adapt to different unsymmetrical load distributions.