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• 저자: 엄태성, 임종진, 문성환, 윤성환, 정재철
• Abstract :This study investigated the flexural behavior of prestressed concrete-encased steel composite beams (PSC composite beam) with hollow core. The PSC composite section consisted of the precast composite element, made of a steel section (H or box section) and U-shaped concrete encasement, and the cast-in-place concrete slab. By prestressing strands at the bottom of the precast element, the cracking resistance was enhanced. In addition, a void was formed in the web to reduce the beam weight. Six full-scale PSC composite beams were tested under positive bending and their flexural behaviors before and after casting the cast-in-place slab were investigated. The test results have shown that the initial strains of the steel section and reinforcing bars that occurred at the prestressing stage agreed well with the predictions by the existing PSC design theory. During the subsequent flexural testing, all beams were failed by concrete crushing at the compression end or slab. The stiffness and strength of the PSC composite beams agreed well with the effective stiffness and plastic moment strength for encased composite members, respectively, calculated in accordance with AISC 360-16. At the interface across the cast-in-place slab, relative slip did not occur and the interface shear resistance was contributed by both the vertical stirrups of the precast concrete encasement and headed studs of the steel element engaged or embedded within the slab.