Engineering Science and Technology, an International Journal (Jan 2025)
Quantifying the impact of construction defects on square RC columns
Abstract
Reinforced concrete (RC) columns are integral to structural integrity, and their performance is highly dependent on precise construction practices. This study investigates the influence of construction defects on the behavior of RC columns, focusing on key parameters such as misplaced longitudinal (vertical) reinforcing bars, honeycombed concrete, variations in stirrup spacing, casting eccentricity, and the effectiveness of square welded wire mesh for confinement. An experimental program was conducted with thirteen square RC column specimens designed to simulate potential construction defects. The findings demonstrate a clear relationship between defect types and column performance. Misplacement of vertical reinforcing bars by up to 50 % resulted in a 17 % reduction in ultimate load capacity. Honeycombed concrete, due to inadequate compaction, was identified as the most harmful defect, leading to a 46 % decrease in ultimate load and a 34 % reduction in toughness. Conversely, reducing stirrup spacing, while maintaining reinforcement quantity, enhanced column performance; a 33 % reduction in spacing resulted in comparable ultimate load but a 36 % increase in toughness. Increased casting eccentricity negatively impacted performance, with a 30 mm eccentricity causing a 46 % reduction in ultimate load capacity. The addition of square welded wire mesh over stirrups significantly improved performance, yielding a 13 % increase in ultimate load, while the use of welded wire mesh alone was ineffective, resulting in nearly a 50 % decrease in load capacity. These results underscore the importance of proper construction practices for the safety and durability of concrete structures. Accurate reinforcement placement, thorough concrete compaction, and precise column alignment are crucial. The research also suggests that using square welded wire mesh alongside stirrups can mitigate some construction defects’ adverse effects. Future studies should explore a broader range of column designs and loading conditions, as well as the effectiveness of various repair and strengthening techniques for columns with existing defects.
