Behavior of Reinforced Concrete Frames with Masonry Infills

Abstract

This report provides a summary of a combined experimental and analytical research
\nproject that investigated the loss of transverse (out-of-plane) strength for
\nun reinforced masonry infill panels as a result of in -plane cracking.
\nLarge-scale test panels were constructed and subjected to repeated and reversed
\nhorizontal forces applied parallel with their plane to a lateral drift equal to twice that
\nat initial cracking. Then, they were subjected to monotonically increasing transverse
\npressures with an air bag until their ultimate strengths were developed. Selected test
\npanels were then repaired and retested.
\nTest specimens consisted of either clay-unit or concrete masonry infills placed in a
\nsingle-bay, single-story reinforced concrete frame. Parameters of the experimental
\nsequence were the masonry-unit type, the mortar type, and the height-to-thickness
\nratio of the infill panel.
\nAn analytical model was developed to predict the out-of-plane behavior and
\nstrength of masonry panels with and without previous in -plane damage. The
\nanalytical model was based on an arching action theory. Analytical model parameters
\nincluded the masonry compressive strength, the infill slenderness ratio, and the extent
\nof in -plane damage.
\nBased on the analytical model and on the supporting experimental results,
\nrecommendations were developed for practical seismic evaluation and rehabilitation
\nof cracked unreinforced masonry infill panels loaded normal to their plane.