Eccentric bearing capacity of steel reinforced reactive powder concrete columns after high temperature exposure

Abstract

The three-dimensional nonlinear finite element model of steel reinforced reactive powder concrete (SRRPC) column was created to analyze mechanical properties after high temperature. Effect of temperature on mechanical behaviors of RPC, section steel and steel bars were taken into account in model. Accuracy of the temperature distribution and the prediction of eccentric bearing capacity after high temperature was verified by comparing experimental results with numerical results. Effects of eccentricity, loading angle, RPC strength, section steel strength and steel ratio on eccentric bearing capacity after high temperature were analyzed. Findings indicate that: there are two typical failure modes of SRRPC columns after high temperature under different eccentric loads, including small and large eccentric compression failure. As eccentricity has increased, residual bearing capacity declines obviously. Increase of RPC strength will greatly increase residual bearing capacity, and improve ductility to a certain extent. Increase of section steel strength and steel ratio can improve residual bearing capacity to a certain extent. Residual bearing capacity is mostly unaffected by the loading angle. Finally, the calculation formula of normal section bearing capacity of SRRPC bias column after high temperature was established based on limit state design method, which has high accuracy and can provide reference for identifying and strengthening composite structures following fire.