关键词: 桥梁工程； 钢内芯-UHPC外包组合结构； U型梁； 装配式结构

Abstract: Urban flyovers often utilize steel box girders due to under-bridge clearance constraints. However, conventional steel box girders are costly to fabricate and maintain. According to this, a steel inner core-UHPC outsourced composite U-beam was proposed, which was with low cost, high construction efficiency and maintenance-free in operation. Finite element analysis model was employed to calculate the stresses, displacements and natural vibration frequencies of the proposed composite beam. The effects of the jacking force applied to the side supports on the structural stresses were analyzed, and the assembly manufacturing and construction methods suitable for this type of structure were also proposed. The research results indicate that the stresses, displacements and natural vibration frequencies of the proposed composite U-shaped beam all meet design requirements. The maximum tensile stress of the structure can be effectively improved by jacking up the side supports. Additionally, the segmental prefabrication and on-site assembly method can shorten the construction period and reduce requirements of construction space.

Key words: bridge engineering; steel inner core-UHPC outsourced composite structure; U-shaped beam; precast structure