Upgrading of ductility and shear capacity of reinforced concrete beams of highway bridge bents

Abstract

Two techniques to upgrade the ductility and shear capacity of reinforced concrete beams of existing highway bridge bents were examined. An experimental program that consisted of 3 scaled models was conducted. The specimens were tested using statically reversed cyclic loading. The first specimen was a control specimen. The beams of the other 2 specimens were upgraded. External steel plates were bonded to the beam in the first upgrading technique and external steel rods were employed in the second upgrading technique. The characteristic behavior of each specimen was experimentally clarified in terms of hysteretic behavior, displacement response ratio, maximum displacement, damage propagation, energy dissipation, equivalent damping factor, and final failure mode. The study revealed that the 2 upgrading techniques could result in enhancement of the overall behavior of the bridge bents. Upgrading the beams utilizing external steel rods, however, was shown to be more effective in resisting future earthquakes. Analytical modeling of the highway frames utilizing FEM was performed. The numerical simulation resulted in a satisfactory accuracy of the predicted behavior. A calibrated baseline FE model was derived and could be employed to quantitatively identify the strengthening effect on resulting behavior of the bridge bents. The study provides an addition to the experimental data for ductility and shear capacity enhancement of bridge bents, and may assist selecting the most appropriate upgrading technique.