Influence of Concrete Cover and Bar Diameter on Development Length in Seismic Zones

The goal of this academic work is to evaluate and analyze the effect of concrete cover and reinforcing bar diameter on the needed development length (Ld) for optimal reinforcement anchoring in seismic zones. Adequate bond strength between concrete and reinforcing steel is critical to ensuring seismic performance and structural safety, especially in areas where plastic hinges develop and large stresses are concentrated.
According to research findings, adding the concrete cover improves the amount of confinement, hence boosting bond strength and resistance to splitting failure. In contrast, as the bar diameter grows, bond strength decreases, needing a longer development time.
Design regulations, like ACI 318, integrate modification factors that account for these impacts and impose extra criteria to assure ductile behavior of reinforced concrete components under seismic stress situations.