BRANDONISIO, GIUSEPPE1; MELE, ELENA2; DE LUCA, ANTONELLO3

1) Assistant Professor, University of Naples “Federico II”, Department of Structures for Engineering and Architecture (Di.St.), giuseppe.brandonisio@unina.it

2) Professor, University of Naples “Federico II”, Department of Structures for Engineering and Architecture (Di.St.), elenmele@unina.it

3) Professor, University of Naples “Federico II”, Department of Structures for Engineering and Architecture (Di.St.), adeluca@unina.it

The paper deals with the problem of evaluating the in-plane seismic capacity of unreinforced masonry structures. In particular, the Limit Analysis approach is used to provide simplified “closed form” expressions of the horizontal collapse multiplier of portal frame, that can be considered the basic structural element in historical multi-storey buildings.

The proposed formulae have been used for performing an extensive parametric analysis on 80 structural schemes, with the aim of understanding the effect of geometry on the portal frame horizontal capacity. A comparison with the results of experimental tests is also provided both in terms of in-plane collapse multiplier and of failure mechanism in order to validate the proposed “closed form” expressions.

The major aim of this study is to provide a simple rule of thumb for the easy assessment of the horizontal strength of simple masonry structures, which can be used for verifying the results of more complex structural analysis such as the nonlinear static analysis.

Keywords: limit analysis, closed form solution, seismic capacity, masonry walls, portal frame, experimental tests