피복두께를 고려한 철근콘크리트 인장부재의 인장증강효과

Abstract

This paper presents the test results of total 12 direct tensile specimens to investigate the effect of cover thickness on the tension stiffening effect in axially loaded reinforced concrete tensile members. Six concrete cover thickness ratio are included as a major experimental parameter. The results show that as thinner the cover thickness is employed, not only more extensive split cracking along the reinforcement is formed, but also the transverse crack spacing become smaller. Thereby, the effective tensile stiffness of the thin specimens at the stabilized cracking stage is much smaller than those of thick specimens. This observation is not considered to the current design provisions, and the significance in reduction of tension stiffening effect by employment of thin cover thickness that would be expected. Based on the present results, a modified tension stiffening factor is proposed for accounting the effect of the cover thickness.