Influence of Masonry Strength and Column Reinforcement on the Lateral Performance of Infilled RC Frames

Masonry infill strength and column flexural, shear reinforcement are the influencing factors in the lateral performance of infilled frame. Various numerical and experimental studies performed in the past decades bring out the beneficial and adverse effects of masonry infilled frame. In this numerically study masonry of different strengths i.e., Concrete Masonry Unit (CMU), Clay Brick (CB), Flyash brick (FA) and Aerated Autoclaved Concrete block (AAC) have been used as infill in a reinforced concrete frame and the behaviour is observed. Similarly, for strong masonry, CMU infilled frame, the flexural and shear reinforcement of column has been varied. From the numerical analysis performed it has been observed that irrespective of the masonry strength all the specimens showed predominant flexural failure of column whereas CMU infilled frame with a flexural reinforcement of 6.4% failed by shear. It is concluded that when the shear capacity of the frame is more than the flexural shear capacity of the frame the failure mode is observed to be flexure.  From the conclusions a simple and effective analytical method for the identification of shear failure in column considering the influence of masonry strength has been proposed.