Investigating the Compressive Strength of Clay Brick Masonry: A Case Study of Nangarhar, Afghanistan

In Afghanistan, masonry structures using burnt clay bricks have long been used for public and private buildings. However, still, there is no standard for masonry structural design based on local material properties. This study investigated the compressive strength of clay brick masonry prisms in Nangarhar, Afghanistan, through experimental testing and finite element modeling (FEM). Three brick classes, with compressive strengths between 8 and 14 MPa, were used to construct prism specimens. The research aimed to propose specific values for masonry compressive strength using local materials and examine the effects of brick strength (fb), mortar strength (fj), joint thickness (tj), and slenderness ratio (h/t) on masonry compressive strength (fm). Test results showed fm values of 17.2 MPa for first-class, 10.0 MPa for second-class, and 7.6 MPa for third-class brick masonry, indicating the influence of the brick’s quality. Key findings showed that an increase in fb causes an equal increase in fm, a 5% increase in fj leads to a 1% increase in fm, a 5 mm increase in tj gives an 8% fm increase, and a 5.5% increase in h/t results in a 1% decrease in fm. The research provides valuable information for evaluating the compressive strength of masonry structures based on the quality of local materials, which can be used to revise Chapter 7 of the Afghanistan Building Code, 2012.