Cyclic response of I-shaped bridge columns with substandard transverse reinforcement

摘要

The cyclic response of a typical bridge column with I-shaped cross-section and substandard transverse reinforcement was investigated by means of experimental and analytical research. The amount of transverse reinforcement was sufficient to ensure adequate shear strength, but other requirements of the Eurocode 8/2 standard related to the confinement and buckling of the longitudinal bars were not fulfilled. Failure was brittle due to the buckling and rupture of the longitudinal bars, which caused a progressive reduction of strength. The results of the experiment showed that the requirements of Eurocode 8/2 (which are quite stringent) related to the minimum volumetric ratio and the maximum centre-to-centre distance of the stirrups along the column, as well as the maximum distance between the engaged longitudinal bars, are justified in the investigated case. It was demonstrated that improperly designed stirrup hooks can cause a significant reduction in the ductility capacity of the column.