Feasibility study of UHPC-NC composite structure in large cantilever system

With the increasing volume of urban traffic, the scale of urban bridges is expanding, and the large cantilever cap beam system is also common. Many scholars have proposed UHPC-NC composite cap beam structure system. Although the UHPC-NC composite structure greatly solves the transportation problem of large-volume prefabricated components, the larger cantilever structure has higher requirements for the strength of UHPC permanent formwork. If the thickness of UHPC formwork is increased, the engineering economy will be greatly reduced. In this paper, aiming at the UHPC-NC segmental pouring composite capping beam system, the bending and shear performance comparison test of UHPC-NC segmental pouring capping beam and ordinary concrete test capping beam is designed. Combined with the finite element analysis results, it is shown that the bearing capacity of UHPC-NC segmental pouring capping beam is compared with the traditional NC beam. The crack resistance is greatly improved, about 76 %, but the ultimate bearing capacity is improved by a small margin, which is mainly related to the bonding performance of the segmental pouring section, which is not related to the position of the section, and the connection mode through the planting bar connection is proposed. The ultimate bearing capacity of the segmented UHPC-NC composite cap beam is increased by about 10 %.