A large number of buildings are realized with masonry infill walls for non-structural reasons since the role of masonry is associated to architectural needs. In this latter cases the structural contribution of masonry infill panels is generally neglected in the structural analyses leading to a significant inaccuracy in the prediction of lateral stiffness, strength and ductility resources of the structure. As highlighted by many authors, ignoring the frame infill panel interaction is not always safe, resulting in a possible change of the seismic demand due to the modification of the fundamental period of the composite structural system. As a consequence the ability to assess the seismic behaviour of masonry infilled reinforced concrete structures is of crucial importance and represent a subject in which many researcher group, in the world, are contributing both from a numerical and an experimental point of view. In this paper a new modeling approach for the simulation of the seismic behaviour of masonry buildings, suitable for current engineering practice applications, is applied for the evaluation of the seismic resistance of nonductile reinforced concrete building. The term nonductile refers to the expected performance of the RC bare frames based on the reinforcement details originally designed to resist gravity loads, with little or no consideration of lateral loads such as wind and seismic. In the employed approach the infilled wall is modelled by means of an innovative discrete element, originally conceived for the simulation of the nonlinear response of masonry building [1], while the reinforced concrete frame is modelled by means of inelastic beam-column element in which the plastic hinges can originate in different positions along the beam-span. The application reported in the paper are relative to real buildings designed during the 1950s and 1960s. The material properties of both reinforced concrete and infilled brick masonry have been derived by the results of numerous experimental campaigns.

Keywords

Masonry Infilled Reinforced Concrete structures, unreinforced masonry structures, in-plane masonry response, macro-element approach.

[1] Calio I., M. Marletta, Panto B. (2012). A new discrete element model for the evaluation of the seismic behaviour of unreinforced masonry buildings. Eng. Struct., Vol. 40,p.  327-338.