Influência de cortes no comportamento mecânico de paredes em alvenaria estrutural submetidas à compressão

Abstract

Chases in masonry walls with no design prediction are often found in Brazilian buildings, usually for electrical, hydraulic, gas, air-conditioning, and other installations. As the wall is the supporting element in this constructive system, a chase can cause significant changes in its mechanical behavior. Both Brazilian and international standards only present limitations for these changes in geometry, but do not provide information about the effect on mechanical behavior when these limits are exceeded. This study pursued the verification of different chase geometries on the structural masonry walls mechanical behavior when submitted to axial loading, through experimental analyzes in small-scale models (1:5). Horizontal, vertical and diagonal Chases with 20%, 30% and 50% depths were considered. Effects of eccentric loading were also analyzed. The increase in chase depth resulted not only in resistance reduction, but also changed the stress-strain behavior, with large deformations and out off plane displacements occurring near failure due to the flexing effects caused by eccentricity generated by the chases. Strains on the moment of rupture were smaller for walls with chases. These effects were amplified for of walls with eccentric loads. The deformation modulus presented significant changes only for walls with 50% chases. The typology that presented the greatest resistance loss was the horizontal chase at half height, followed by the top horizontal and finally diagonal chase. Masonry walls with vertical chases do not show differences in the mechanical behavior in relation to the reference walls. Finally, correlations between chase depth and net area reduction with resistance loss were developed, being this last analysis a linear relationship.