Prediction of Seismic Performance Levels of Corroded Reinforced Concrete Columns as a Function of Crack Width

Abstract

An experimental study was conducted for the prediction of the seismic performance levels of corroded reinforced concrete (RC) columns as a function of the initial corrosion crack widths. A full-scale accelerated-corrosion pool was used to corrode 25 full-scale RC columns. The initial crack widths at different levels of corrosion were measured for three different concrete strength levels: 9, 27, and 37 MPa. The seismic performance levels of corroded RC columns under combined cyclic lateral-displacement excursions at two different axial-load ratios (0.20 and 0.40) were measured. The corrosion levels obtained for the initially measured corrosion crack widths were used for establishing a correlation with the lateral-displacement capacities of the RC columns according to an energy-based method. Three empirical models were developed. The first was for predicting the cross-sectional area reduction of reinforcement bars according to the initial corrosion crack widths. The second model was for predicting the percentage of energy capacity of RC columns as a function of the drift ratio and corrosion levels. The third model was for predicting the seismic performance levels of RC columns as a function of the initial corrosion crack widths and was used for an in situ structural assessment. The experimental test results showed that above a 2% drift ratio, all uncorroded RC columns (regardless of the concrete strength levels) exhibited a sudden reduction in energy capacity, and their total energy capacity was consumed. In the case of corrosion, the energy capacity of concrete with high strength levels was prematurely exhausted above a 1.4% drift ratio because of the effects of the corrosion products under the high strength levels of the concrete.

An experimental study on seismic performance levels of highly corroded reinforced concrete columns

“…As shown in Figure 13, although the compressive strength of the current study was within the limits of the model proposed by Yalciner et al, 28 the developed model underestimated the current experimentally measured reduction in the cross‐sectional area. This was because of the limited crack widths of the concrete after the corrosion propagation process.…”

“…Figure 19 shows the percentage of remaining energy capacity of the corroded RC columns in the present study and experimental data obtained from the study by Yalciner et al 28 The corrosion levels obtained from the study by Yalciner et al 28 are also shown in Figure 18 for comparison.…”

“…The proposed model in the present study considers both not buckling (i.e., Yalciner et al 28 ) and buckling of reinforcement bars (i.e., present study) for given lower and higher corrosion levels, respectively. As it is well known, even the buckling of uncorroded reinforcement bars is based on bar diameters, applied axial load ratios, and particularly confinement effects by stirrups.…”

“…In that study, the developed models were based on dissipated energies determined based on the roof drift ratios with an interval of 0.1% and limited to the drift ratio of 2%. Therefore, in the current study, the authors developed the following empirical models to predict the percentage of energy capacity of uncorroded RC columns by considering the current and experimental data obtained from Yalciner et al 28 where E uncorroded is the remained energy capacity of uncorroded RC columns and δ is the drift ratio. The data obtained using the proposed model and the experimental data obtained from Yalciner et al 28 were inserted into the newly proposed models.…”

“…Positive loading direction Negative loading direction Bilateral failure criteria and experimental data obtained from the study by Yalciner et al 28 The corrosion levels obtained from the study by Yalciner et al 28 are also shown in Figure 18 for comparison.…”