Mesoscopic investigation on seismic performance of corroded reinforced concrete columns

In addition to the normal service loadings, engineering structures may be subjected to occasional loadings such as earthquakes, which may cause severe destruction. When the steel rebar is corroded, the damage could be more serious. To investigate the seismic performance of corroded RC columns, a three-dimensional mesoscale finite element model was established. In this approach, concrete was considered as a three-phase composite composed of aggregate, mortar matrix and interfacial transition zone(ITZ). The nonlinear spring were used to describe the bond slip between steel and concrete. The degradation of the material properties of the steel rebar and cover concrete as well as the bonding performance due to corrosion were taken into account. The rationality of the developed numerical analysis model was verified by the good agreement between the numerical results and the available experimental observation. On this basis, the effect of corrosion level, axial force ratio and shear-span ratio on the seismic performance of corroded RC columns, including lateral bearing capacity, ductility, and energy consumption, were explored and discussed. The simulation results indicate that the mesoscopic method can consider the heterogeneity of concrete, to more realistically and reasonably reflect the destruction process of structures.