A Baratta and I Corbi
Department of Structural Engineering, University of Naples, Naples, Italy

In this paper in order to study the behaviour of a masonry wall, the Not Resisting Tension (NRT) model is assumed. Then a computational procedure for two-dimensional equilibrium problems, which are representative of the behaviour of masonry walls loaded by in-plane forces, is reported. The solution is searched for by an optimisation procedure according to the conjugate gradient method interpolated with relaxation intermediate steps. The procedure is tested from the point of view of accuracy and convergence with reference to a masonry wall with openings, stringcourses and architraves, subject to horizontal loading.
In the second part of the paper, data from laboratory experiments on masonry panels under lateral loads is reported and compared with the results relevant to an FEM no-tension model of the specimen, which are obtained by numerically implementing the described theoretical approach. The same experience is also repeated in the case of some FRP reinforcement, providing a comparison with theoretical data in this case also.
In both cases, experimental and analytical results appear in excellent agreement thus validating the general theoretical approach, even for the reinforcement model and in its coupling with the masonry model.

Key words
Structural analysis; Optimisation; NRT model; FEM; Potential; masonry panel; FRP reinforcement