Analysis of the collapse mechanisms in uncracked arches: The role of friction forces and stereotomy in masonry

This paper examines the stability of uncracked masonry arches for the purpose of exploring their collapse mechanism. Two situations that warrant analysis may occur during the lifetime of a voussoir arch that forms part of a structural system in a heritage construction. The first situation is related to the stability of the arch before the appearance of hinges or relative displacements (sliding) of a group of voussoirs with respect to an adjacent uncracked arch. The second situation is related to the stability of the cracked arch when some damage has already occurred.The first of these situations is analyzed in this paper, with the goal of detecting where damage will initiate. The classical stability conditions of a group of voussoirs Gij considered as a whole within the arch are considered to apply. The movement of a solid in a plane has three degrees of freedom: two translations (one in each coordinate axis) and one rotation with respect to the normal axis to the plane where the 2D solid is contained. All possibilities of movement of any Gij group have been analyzed. An arch with a radius of 100 cm at the intrados was constructed of wood in a laboratory to observe its collapse mechanism. The collapse of the arch can be predicted analytically.

► Paper is related to the stability of an historical arch before the appearance of damage.
► The friction forces and the stereotomy are relevant for masonry stability.
► The stability criterion is the only relevant for structural behavior of masonry arches.
► It has been formulated all the possibilities of imminent movement of an arch.
► The experimental collapse reproduces very close the analytical considerations.