Author(s)

V. Quintas

Abstract

The use of lines of thrust to asses the stability of masonry arches, has became very popular on last years. Nevertheless, this form of analysis can be not sure in some cases. The real requirement for the stability of arches is that excentricity of normal forces lies into the depth of the arch. It has been proposed that the same is true for lines of thrust. This paper shows that in many instances the latter is not the necessary condition. 1. The general principles of the stability of masonry As it is well known, a cracked masonry structure can support a bending moment M if an axial force N acts simultaneously. As it can be shown in figure 1. compressions due to normal force form a pair with this force. A' • d. that counteracs bending moment.

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