Abstract: Uniaxial tensile tests were conducted on four full-scale strip model members of the section steel-UHPC composite deck structure (two deck members composed of UHPC+section steel and two joint members composed of UHPC+section steel+steel bar). The strain and crack development law of the member was analyzed. ABAQUS software was used to establish the finite element model and simulate the whole test process, and the development law of the axial deformation of members and the strain of section steel and steel bar were analyzed. The results show that, for the deck members, the section steel and UHPC thin plate have good cooperative mechanical performance, and the tiny cracks are densely distributed until the section steel yields, and 2～3 main cracks are generated in the UHPC thin plate. For the joint members, as the loading progresses, the initial microcracks appear at the interface between the new and old UHPC, and the subsequent microcracks are mainly concentrated at the lower step until the steel bar embedded in the lower step yields; the joint member is damaged, and a single main crack is formed at the lower step. For the UHPC axial deformation value of deck members and joint members, the section steel strain value of deck members or the steel bar strain value of joint members, the ABAQUS calculation results are in good agreement with the test results.

Key words: bridge engineering; section steel-UHPC composite deck structure; uniaxial tensile test; deck members; joint members; crack

摘要： 针对型钢-UHPC组合桥面结构的4个足尺条带模型构件（UHPC+型钢组成的桥面板构件2个，UHPC+型钢+钢条组成的接缝构件2个），开展了单轴拉伸试验；分析了构件的应变和裂缝发展规律；采用ABAQUS软件建立有限元模型模拟试验全过程，分析了构件的轴向变形及型钢、钢条的应变发展规律。结果表明：对于桥面板构件，型钢与UHPC薄板具有良好的协同受力性能，细微裂缝密集分布，直至型钢屈服，UHPC薄板产生2～3条主裂缝；对于接缝构件，随着加载的进行，初始微裂缝出现在新旧UHPC交界面处，后续微裂缝则主要集中于下台阶处，直至下台阶处内部埋置的钢条屈服，接缝构件破坏，下台阶处形成单一主裂缝；对于桥面板构件和接缝构件的UHPC轴向变形值及桥面板构件的型钢应变值或者接缝构件的钢条应变值，ABAQUS计算结果与试验结果吻合较好。

关键词: 桥梁工程；型钢-UHPC组合桥面结构；单轴拉伸试验；桥面板构件；接缝构件；裂缝