Chair of Structural rehabilitation, University of Bologna, ITALY, DICAM Department
PELA’, L.University of Bologna, ITALY, DICAM Department
University of Sao Paulo, BRAZIL, Structural Engineering Dept.

Assessing the collapse load for complex masonry structures, such as historic monuments, is a very hard task and looking for a reliable and suitable procedure considering all the available numerical techniques is still under debate. One interesting and simple approach for wide modelling capabilities is based on the discretization of the masonry structure as a system of truss elements with appropriate constitutive law. According to this procedure, the inclusion of reinforcement elements is a simple operation of adding bars representing the reinforcement net.
This approach presents several favourable features. First of all, after cracking, masonry behaves as a system of thrust wedges which are very similar to a reticular frame. Secondly, shear and flexural mechanisms are clearly distinguished but derive from a single constitutive law valid for all the elements composing the model. Finally, some specific problems, such as multiple leaf walls or curved shells, can be solved in the same way as ordinary in-plane loaded walls.
Initially, some very simple representation rules needed to construct the equivalent reticular model of common masonry structures are presented in detail. Some updated topics, such as adding FRP reinforcement to masonry models are also addressed. Next, the results obtained for some experimental tests are compared with those obtained by means of several numerical simulations, including the procedure proposed in this paper. Finally, some interesting conclusions are stated, showing that the reticular simple model presented in this paper produces very good results.

Key words
Masonry, reticular models, non linear analysis, multiple leaves, FRP reinforcement