Stability Assessment of Masonry Arches Deformed by Thermal Distortions

Masonry arches and vaults are widespread in historical buildings and infrastructures. The shape of these structures is a crucial aspect for their equilibrium condition and is responsible for their safety. Their current shape can be different from the design one, because it may have been affected by deformations caused by various phenomena over time, such as load changes, earthquakes, foundation settlements and temperature raising/lowering. It follows that the current safety verification must be done by comparing the load thrust line with the current deformed shape of the arch. The paper investigates the effect of thermal distortions on the original shape of the arch and the safety condition, through a rigid-block and lumped deformability model. Thermal distortions are assigned at the joints. The effect of thermal distortions on masonry arches is investigated by assessing the increase or decrease of the load bearing capacity. To this aim, the behavior of an arch case study is investigated by applying an increasing point load and ranging the thermal gradient. A parametric analysis is also performed to assess the effect of the tensile strength of joints.