도넛형 이방향 중공슬래브 뚫림전단 강도 및 파괴거동에 대한 실험적 연구

Abstract

This paper presents the punching shear strength and failure behavior of biaxial hollow slab with donut type hollow-shaper. Until now, various types of slab systems which can reduce self-weight of slabs have been studied as the height and width of building structures rapidly increase. A biaxial hollow slab system is widely known as one of the effective slab system which can reduce self-weight of slab. According to previous studies, the biaxial hollow slab has weakness in slab-column connection compared with solid slab. And previous studies pointed out reduced cross-section area of concrete by hollows as the cause. It is assumed in this study that the shape of hollows and the location of hollow-shaper exert influence on the punching shear strength of biaxial hollow slabs. Therefore, donut type hollow-shaper which was suggested as the optimal hollow shape in previous study was used in this study. To verify the punching shear strength and failure behaviour of donut type biaxial hollow slab, punching shear tests were conducted. 4 test specimens were used for test parameters. One was conventional RC slab and 3 were hollow slabs. The test parameter was the area of critical section which were determined by the number of hollow-shaper around the column. The punching shear strength of the donut type biaxial hollow slabs are 87%∼103% of solid slabs and superior to generic biaxial hollow slabs. And punching shear cracks occurred at the first perimeter line of donut type hollows.