Improving In-Plane Behavior of Weak Brick Masonry Walls Through Assimilation of Partially Confining RC Bands

Abstract

ABSTRACT In this work, a numerical study is conducted to investigate the improvement of in-plane behavior of weak brick masonry walls through assimilation of partially confining horizontal and vertical reinforced concrete (RC) bands. The bands are considered to be assimilated with the existing walls by cutting grooves over the partial thickness of the wall in a easy-to-construct manner. For numerical modeling of the wall width and without partially confining elements, a three-dimensional (3D) macro-modeling approach is utilized as it is computationally efficient compared to other modeling approaches while representing the global behavior reasonably well. The components of macro-models are discretely modeled. The concrete damage plasticity (CDP) model is considered to describe the non-linear behavior of the concrete and masonry for crushing and cracking failures. Steel reinforcements are considered as bilinear with hardening and modeled with perfect adhesion with the surrounding concrete using embedded constraints. Experimental results obtained from the full-scale tests at the Structural Engineering laboratory of IIT Kanpur have been utilized to validate the numerical model. The responses obtained from the numerical model of both with and without RC bands demonstrate that the models reasonably capture the experimental behavior such as initial stiffness, peak loads and post-peak behavior. The initial peak load from the numerical model of without and with RC bands was found to be 3.2% and 6.9% lower than the experimental value, respectively. Although post-yield trends of numerical and experimental results show similar behavior for walls without and with RC bands, the numerical model underestimates the post-yield strength for the wall without RC bands. This deviation can be attributed to the masonry dominated post-peak behavior coupled with modeling assumptions and values of model parameters used for the numerical analysis. Finally, to understand the influence of various parameters on lateral strength, a parametric study has been conducted. From the parametric study, it has been found that the compressive strength of masonry and band aspect ratio are the two most important parameters governing the strength of the wall. Finally, it is noted that a wall with band aspect ratio close to unity provides superior ductile behavior.