A non-linear masonry infill macro-model to represent the global behaviour of buildings under cyclic loading

Abstract

The presence of masonry infill walls in RC buildings is very common. However, even nowadays, in the design of new buildings and in the assessment of existing ones, the infills are usually considered as non-structural elements and their influence in the structural response is ignored. For horizontal loading, infill panels can drastically modify the response, attracting forces to parts of the structure that have not been designed to resist them (Varum, 2003). In this paper is presented an improved non-linear numerical model for the simulation of the influence of the masonry infill walls in the seismic behaviour of structures, implemented in the analysis program PORANL. After the implementation and calibration of the proposed masonry model, it was performed a series non-linear dynamic analyses of a building, representative of the Modern Architecture. The main objective was to investigate the behaviour of this type of buildings, and their weakness under seismic loading. The building geometry and dimensions of the RC elements and infill walls were given in the original project, and were confirmed in the technical visits. The building studied has nine storeys and the structure is mainly composed by twelve plane frames oriented in the transversal direction. The building was analysed with a simplified plane model, for each direction, and the existing infill panels were considered according to their dimensions and location. The earthquake action adopted in this study was simulated with three series of artificially generated earthquakes, for a medium/high seismic risk scenario in Europe.