Effect of the edge support conditions on the performance of masonry infill walls subjected to out of plane loading

Abstract

Serious damage and loss of stability of masonry in fill walls can be realized when the infill panel is subjected to in-plane and out of plane loading. To improve their performance, the edge support conditions between the infill walls and the bounding frames needs to be properly investigated and improved. A survey of fifty (50) structures under construction in the Kampala City Council Authority revealed that 94% of the structures construct an RC frames and incorporate masonry infills. The four observed methods of infill construction are; Wall supported on beam at the bottom and bonded by mortar to the side columns and top beam (20%), wall bonded to side columns by mortar but top beam cast with its soffit directly on the wall (28%), side columns cast with infill wall panel in place and the soffit of the top beam cast directly on the wall (36%), side column cast with Infill panel in place forming a saw tooth pattern with the columns and soffit of the beam cast directly on the wall ( 10%) and infill wall panel built into structural steel frame connected by metal plates (6%). A questionnaire of twenty (20) leading consultancy firms in Uganda revealed that 19 has never incorporated infill edge support in design and construction but only design for bracing beams in infills to prevent failures. Four different configurations of the edge supp01t conditions above were evaluated using the general finite element software, ABAQUS. An out of plane distributed load was applied to the wall panels to cause out of plane failure for each of the four selected configurations. The results showed that masonry infill walls that have the soffit of the beam constructed directly on the wall and restrained by saw toothing RC columns yield better performance.