Effect of axial restraint on flexural and shear behaviour of high-strength concrete members

Abstract

This paper was developed to examine the effect of sequential axial restraint on flexural and shear behaviour of high-strength concrete beams. This study includes flexural and shear tests conducted under both restrained and unrestrained conditions to provide a comparison in test results. In the early stage of the tests, the bending stiffness of the fully-restrained beam was lower than that of the unrestrained beam due to a crack generated by tensile restraint during concrete curing. However, as the transverse load increased, the restraint force changed from tension to compression, causing the stiffness to be higher. Even though the displacement capacity of the restrained beam at failure decreased, the yield load and displacement of the restrained beam was higher than that of the unrestrained beam. Additionally, it was observed that shear crack propagation and shear capacity were not affected by cracks less than 0·1 mm in width, which penetrated due to the restraining tensile stress that occurred before loading.