Cracking and Crack Width Patterns in Large Masonry Beams

Abstract

Earlier studies on large reinforced concrete (RC) beams found that the width of side-face cracks can be larger than the width of cracks at the extreme tension face. Accordingly, many RC design standards and codes recommend using skin reinforcement to limit the width of side-face cracks. In large reinforced masonry (RM) beams, side-face cracks and skin reinforcement are known as intermediate cracks and intermediate reinforcement, respectively. In line with the studies on large RC beams, it is intuitively presumed that the width of intermediate cracks in large RM beams can be critical for serviceability requirements. Accordingly, the Canadian standard CSA S304.1 recommends using intermediate reinforcement in large RM beams, although no research was conducted to validate this. Hence, this study was completed to understand the cracking pattern in large RM beams and the beneficial effect of intermediate reinforcement as recommended in the Canadian standard. The study found that the cracking pattern in large RM beams is different from that of large RC beams. This study also found that the recommendation of CSA S304.1 on intermediate reinforcement for large RM beams does not yield the best use.