립ㄷ형강과 측면사다리꼴 강판을 사용한 U형 합성보의 구조성능에 대한 실험적 연구

초록

In this study, experiments were conducted to investigate the structural performance of U-shaped steel-concrete composite beams utilizing cold-formed lipped channels as web members. Trapezoidal steel plates were additionally installed on both lower sides of the beams to enhance flexural and shear capacities. A total of five specimens were fabricated with two primary variables: the presence or absence of bottom tension reinforcement (R/NR) and different shear span-to-depth ratios (1.5, 2.0, and 2.5). Four-point bending tests and three-point shear tests were performed respectively to evaluate the flexural and shear behaviors. The specimens designed for flexure exhibited typical flexural failure modes. Specifically, specimen T8-R, containing bottom tension reinforcement, exhibited approximately 14.8 % higher flexural strength compared to specimen T8-NR without bottom tension reinforcement. Specimens subjected to shear tests showed typical shear failure patterns, and experimental shear strength decreased as the shear span-to-depth ratio increased, with a maximum reduction of about 15 %. The cold-formed lipped channels provided effective shear connection, enabling a fully composite action between the steel and concrete components, thereby potentially replacing conventional stud anchors. This composite action significantly enhanced the overall structural performance, improved load distribution capacity, and contributed to the stability and robustness of the entire structural system.

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