Lateral stiffness of brick masonry in filled plane frames

In a companion paper, a new finite element technique for the analysis of brickwork infilled plane frames under lateral loads has been presented. In the present paper, the influence of the masonry infill panel opening in the reduction of the infilled frames stiffness has been investigated by means of this technique. A parametric study has been carried out using as parameters the position and the percentage of the masonry infill panel opening for the case of one-story one-bay infilled frame. The investigation has been extended to the case of multistory, fully or partially infilled frames. In particular, the redistribution of action effects of infilled frames under lateral loads has been studied. It is shown that the redistribution of shear force is critically influenced by the presence and continuity of infill panels. The presence of infills leads, in general, to decreased shear forces on the frame columns. However, in the case of an infilled frame with a soft ground story, the shear forces acting on columns are considerably higher than those obtained from the analysis of the bare frame.