新型装配式双舱综合管廊节点的力学性能试验

Experimental study of mechanical properties of joints in a new-type prefabricated double cabin utility tunnel

预制装配综合管廊结构中,节点是结构的薄弱环节,其力学性能直接影响整体结构的变形和承载力等.本文提出了一种"U型套箍插筋连接"新型装配式双舱综合管廊结构,通过4个节点足尺试件力学性能试验,包括1个底部L型现浇边节点试件,1个底部L型装配边节点试件,1个顶部L型装配节点试件和1个底部T型装配节点试件,以此来验证"U型套箍插筋"连接技术的有效性.试验得到了节点足尺试件的开裂荷载、裂缝发展规律、承载能力、破坏方式、构件延性等力学性能.试验结果表明:新型装配式管廊节点试件都在靠近角点区域发生弯剪破坏,具有较高的承载力和延性;采用"U型套箍插筋"连接性能可靠,能够获得与现浇节点试件相当的力学性能.

Modernization of urban infrastructure is the premise for improving urban operation efficiency. The traditional direct burying method of the municipal public pipeline requires repeated excavation for maintenance, which seriously affects the traffic and appearance of the city and interferes with the everyday life and work order of residents. With the rapid development of urbanization recently, the city’s underground utility tunnel appears at a historical juncture. To cope with the industry’s urgent need for efficient and green construction technology, China is strongly promoting urban utility tunnels and its development toward prefabrication. The prefabricated utility tunnel efficiently uses the urban underground space, intensively manages various municipal pipelines, and solves the" zipper road" problem;it also has the advantages of increased production efficiency in a short construction period and green environmental protection. The joint is the weakest link of the structure in a prefabricated utility tunnel, and its mechanical properties directly affect the deformation and bearing capacity of the entire structure. A new type of prefabricated double cabin utility tunnel with a" U-shaped ferrule joint bars connection" was proposed. The validity of the method was confirmed through testing the mechanical properties of four full-scale joints, including one bottom L-shaped cast-in-place side joint, one bottom L-shaped assembly side joint, one top L-shaped assembly joint, and one bottom T-shaped assembly joint specimen. The result obtained the mechanical properties of the joint full-scale specimen, such as cracking load, crack development law, bearing capacity, failure mode, and member ductility.Furthermore, the specimens of new prefabricated utility tunnel joints had flexure-shear failures near the corner points despite their high bearing capacity and ductility. Using U-shaped ferrule joint bars provides consistent performance and can obtain mechanical properties comparable with those of cast-in-place joint specimens.