Bond strength and confinement in reinforced concrete

The strength assessment of existing reinforced concrete structures is challenging when deterioration and detailing deficiencies are present. The anchorage of the internal steel reinforcement can be critical under particular confinement conditions of external pressure, concrete cover and transverse reinforcement. The in-teraction between different confinement contributions and their effects on bond were investigated with a novel experimental set-up that removed the parasitic support pressure. With significant transverse reinforcement and varying concrete cover, maximum bond strengths were obtained for intermediate cover-to-diameter ratios. The transverse reinforcement contribution depended on the occurrence of splitting cracks. These findings can lead to improved assessment and maintenance strategies.