Ductility of Eccentrically Compressed Elements of RC Frame Damaged by Corrosion under Accidental Impacts

The impact of aggressive environments and, accordingly, the corrosion damage of concrete and reinforcing steel, the violation of adhesion between them in some areas lead to a change in the values of the limiting height of the compressed zone, which determine the plastic or brittle mechanism for the destruction of structures of reinforced concrete frame buildings. The purpose of the presented study was to assess the influence of the depth of corrosion damage on the ultimate height of the compressed zone of the section of eccentrically compressed elements of reinforced concrete frames of buildings, as well as to assess the bearing capacity of these elements. The article presents analytical dependences for estimating the limit value of the height of the compressed zone of the section of a corrosion-damaged reinforced concrete element of the building frame with a two-line approximation of the state diagram of concrete.It has been established that an increase in the depth of corrosion damage leads to a decrease in the height of the compressed section zone relative to the part of the working height of the section that retained the resource of force resistance, as well as to a decrease in the bearing capacity of eccentrically compressed reinforced concrete elements due to a decrease in the effective working height of the section and an increase in their flexibility. An increase in the flexibility of the elements leads to a decrease in the magnitude of the limiting longitudinal force perceived by eccentrically compressed reinforced concrete elements. At the same time, an increase in the relative depth of corrosion damage enhances this effect due to an increase in the effective flexibility of such elements compared to elements without damage.