Stability of a reinforced concrete column under compression with torsion caused by accidental action

Abstract

Under emergency situations associated with sudden failures of the load-bearing elements of the structure, torques may additionally occur in the columns due to the specifics of the structural design of the buildings. Thus, the columns may be in a complex stress-strain state. The objective of this study was to develop a semi-analytical design model for analysis of the stability of reinforced concrete columns subjected to compression with torsion as a result of an accidental action. For achieving the objective, authors formulated the initial hypotheses, developed the determining equations for calculating the stability of a reinforced concrete column subjected to compression with torsion. To validate the reliability of the proposed model, it has been compared with the results of modeling in the software complex Ansys. Analysis of the data showed that the largest difference between the results was up to 8.08% for the case P = 0.4·Pcr,e = 126.6 kN. The smallest difference of 3.6% was for the case P = 0.9·Pcr,e = 284.85 kN. It has been shown that as the torque increases, there is a decrease in the value of the critical force causing loss of stability. This is due both to the action of the torsional pair of forces during the distortion of the rod and to the decrease in the mechanical properties of concrete under the combined action of normal and tangential stresses.