Effect of axial restraint on mechanical behavior and average crack spacing of reinforced concrete flexural members

Abstract

This study was performed to verify the effect of axial restraint on the mechanical behavior and average crack spacing of reinforced concrete (RC) flexural members. Experiments for mechanical behavior have been performed on axially restrained and unrestrained RC beams. And, the average crack spacing has also been investigated in other RC beam tests under the axially restrained condition. The test results show that the capacity of the axially restrained beam was higher than that of the unrestrained beam. For restrained flexural members, axial deformation was restrained, deformation capacity was decreased, plastic behavior was delayed, and possibility of compressive failure was increased due to the axial restraint force. The major variables affecting the average crack spacing were steel stress, axial force, circumference of reinforcing bar, and effective tension area of concrete. However, the effect of concrete compressive strength was minimal. A prediction equation utilizing the identified variables was proposed for determining the average crack spacing of the axially restrained RC flexural members.