To study the impact of corrosion of both longitudinal bar and stirrup on the bonding performance of steel bar and concrete

we fabricated 25 corroded reinforced concrete (RC) specimens by the accelerated corrosion method of electroosmosis-constant current-dry wet cycles. Pullout tests were carried out on the specimens

and the influences of parameters such as longitudinal bar corrosion

stirrup corrosion

cover thickness

and stirrup spacing on bonding properties were studied. The effect of corrosion on the bonding force between concrete and steel bar was analyzed

and the degradation of the bonding performance was attributed to the reduction of the material behavior and the degradation of the constraint effect. On the basis of the test results

a modified bondslip constitutive model was established and verified considering design parameters and both corrosion of longitudinal bar and stirrup. A stressslip model of corroded longitudinal bar was obtained by combining the proposed constitutive model and infinitesimal algorithm. In the OpenSees platform

the stressslip model was applied to the zero-length section element

and the numerical model of corroded RC components considering bondslip behavior was established by adopting fiber-based beam-column element and zero-length section element. The accuracy of the model was verified according to the quasi-static test data of the corroded RC column

and the fiber model considering only corrosion damage was used for auxiliary verification. Results show that the bonding force between concrete and steel bar increased first and then decreased with the increase in the corrosion degree. Increasing the cover thickness could slightly improve the bonding force

while the increase in stirrup density could significantly improve the bonding force. Compared with the fiber model

the bearing capacity

cumulative energy dissipation

and ultimate displacement errors were reduced by 12.8%

23.5%

and 14.2% in the constructed fiber model

indicating that the constructed model can reasonably calculate the contribution of steel bar slip and accurately predict the overall seismic response of the corroded RC columns.