Abstract
This study experimentally investigates the strength, behavior and calculation of torsional strength of steel reinforced concrete (SRC) members subjected to pure torsion. Sixteen beam specimens were designed to include design parameters of structural steel, closed stirrup, and longitudinal reinforcement. Test results indicate that the SRC beams, enclosed the H-shaped structural steel, reached slightly higher torsional strength than reinforced concrete beams did due to the low torsional resistance of the H-shaped structural steel. However, the torque-twist curves for SRC specimens were different from those for RC specimens. The torsional strength of the SRC specimens gradually decreased and possessed better toughness after reached the peak strength as indicated in the torque-twist curves. Increasing the amount of closed stirrups can enhance the torsional strength of the SRC specimens. Specimens with No. 3@10 cm closed stirrups can develop higher torsional strength than calculated strength followed the code, while specimens with 2-No. 3@10 cm closed stirrups can not even attain the strength calculated by the code. Specimens enclosed different size of the structural steel did not achieve consistent test results. In addition, increasing the amount of longitudinal reinforcement can increase the torsional strength. Nevertheless, the effect becomes little for specimens with higher amount of closed stirrups. The structural steel did not yield while the SRC specimens reached the ultimate torsional strength. Because the negligible contribution to the torsional strength compared with RC beam, the H-shaped structural steel can be conservatively neglected to calculate the torsional strength of SRC beam in practical design.