RESTORING FORCE CHARACTERISTICS OF RC COLUMNS WITH HIGH-STRENGTH CONCRETE AND STEEL BARS UNDER AXIAL TENSION FORCE

摘要

This research discusses the restoring forces characteristics of RC columns under axial tension force. This paper presents the review of typical experimental data and proposes a restoring force characteristics model of RC columns with high strength concrete and high strength steel bars under axial tension force. Fourteen RC column specimen tests were carried out under varying axial forces to simulate the case of lower story columns of high-rise RC buildings under earthquake loading with high strength concrete, over 100MPa, high strength steel fiber reinforced concrete up to 171MPa and high strength longitudinal bars up to 1201MPa. This research presents the restoring force characteristics model of a multi linear model connecting three characteristic points defined as the elastic breaking point, tensile flexural yielding point, and the R-20 strength points, with respect to the restoring force characteristics of the tested high-strength concrete columns under axial tension forces. The R-20 point is relative to the flexural strength at the drift angle -0.02 rad. It has been verified from the results that the restoring force characteristics of the model proposed in this research are applicable to properly assess the restoring force characteristics (at the drift angles up to -0.02 rad of high-strength (steel fiber) concrete columns under axial tension forces.