Masonry-infilled frames are composite systems consisting of frames made either of steel or concrete, and the infill usually of bricks. While it is obvious that infill increases the stiffness of the frame structure under working loads its behavior under extreme loads is unknown and therefore treated with caution. The analytical model used in the design process should directly incorporate the infills, rather than being based on the analysis of the bare frame with essentially empirical corrections (magnification) of the design actions, as suggested in Eurocode EN 1998-1. The only feasible way to account for the negative effects of irregularly arranged infill walls, but also for the positive effects of the infill which act effectively as a ‘ first line of defense’ in the structure, is to directly include the infill walls in the analytical model used for design. Rehabilitation of buildings to improve the seismic behavior is being widely used all around the world. Infilling of the frames with panels presents a viable perspective. Simplified design methods, that reliably represent the behavior of structures with infill, are necessary for enabling parametric analysis in the design phase as well as fast evaluation of the existing structures. In this article we tried out the possibilities of linear model for infill to simulate the nonlinear behavior of infilled-frame systems on a model structure. That is also a first step towards improving and making the seismic modeling of infill frames simpler.

Civil engineering