Yalciner, Hakan; Kumbasaroglu, Atila

To perform accurate seismic analyses of corroded reinforced concrete (RC) buildings, it is necessary to predict the bond-slip relationships to modify the moment-curvature relationships. In this study, empirical models were developed to predict the bond strength of corroded RC columns. Twenty-five RC columns were tested under combined cyclic lateral displacement excursions for three concrete strength levels-specifically, 9, 27, and 37 MPa (1305, 3915, and 5365 psi, respectively)-at two axial load ratios of 0.20 and 0.40 and at four corrosion levels. An accelerated corrosion method was applied to corrode the reinforcing bars embedded in the RC columns. The actual corrosion levels were determined by breaking the concrete and extracting all the longitudinal and transverse reinforcing bars from the RC columns. Three empirical models were developed. The first model was used to predict the development length of the corroded reinforcing bars. The second and third models were used to predict the bond strength and slip in the reinforcing bars as a function of the corrosion levels. The results indicated that previous models that predict the bond strength of corroded RC members were limited because of the theoretically considered development length of the noncorroded reinforcing bars.

Yalciner, Hakan; Kumbasaroglu, Atila

A total of 30 full-scale reinforced concrete (RC) columns were tested to develop models for the prediction of the structural behavior of corroded RC columns. Of these, 25 RC columns were tested under cyclic loading for two different applied axial load ratios-namely, 0.20 and 0.40-at three concrete strength levels-namely, 9, 27, and 37 MPa (1305, 3915, and 5365 psi)-and at four corrosion levels. Five RC columns were loaded monotonically with an axial load ratio of 0.20 at four corrosion levels to calculate the damage index. The actual corrosion levels were obtained by breaking the concrete and extracting all the reinforcing bars. The test results demonstrated that the ductility ratios of the corroded RC columns, which were not determined in accordance with energy-based or bilateral failure criteria, could be misleading. The determined energy dissipation capacity and damage index of the columns further revealed the corrosion effects.

Yalciner, H.; Kumbasaroglu, A.; El-Sayed, A.K.; Balkis, A. Pekrioglu; Dogru, E.; Turan, A.I.; Karimi, A.; Kohistani, R.; Mermit, M.F.; Bicer, K.

An experimental study was conducted to predict the flexural strength of corroded full-scale reinforced concrete (RC) beams. Two different concrete strength levels at two different steel ratios were tested for different corrosion levels ranging from 0 to 17%. An accelerated corrosion aging method was applied to corrode the reinforcing bars embedded in concrete. The actual corrosion levels were obtained by breaking the concrete and extracting the reinforcing bars. A practical model was developed for the prediction of the flexural strength of corroded RC beams. The developed model predicted the experimentally obtained flexural strength of corroded beams found in the literature well. The results revealed that the structural behavior of corroded RC beams requires consideration of the corrosion levels at both the tensile bars and the stirrups (which are more exposed to corrosion because of their use as outer reinforcing bars) and have significant effects on the flexural strength of corroded RC beams.