混合梁斜拉桥钢混结合段试验研究技术新进展

NEW DEVELOPMENT OF THE EXPERIMENTAL RESEARCH ON STEEL-CONCRETE COMPOSITE JOINT OF COMPOSITE BEAM CABLE-STAYED BRIDGE

钢混组合梁桥充分发挥了钢和混凝土各自的材料性能优势。混合梁桥结合段由钢梁、剪力钉、钢绞线、钢承压板和混凝土梁等构成。从整体上来看,该位置存在材料和刚度的突变,导致其传力机理和施工工艺复杂,成为混合梁桥方案研究的重点问题。因此,开展该构造的研究对拓展混合梁桥的应用空间具有重要现实意义。20世纪90年代以后,钢混组合结构在我国发展迅猛。由于缺乏足够设计方法的支撑,实施了大量针对钢混结合段力学行为的试验研究来验证其设计构造的可行性和合理性。通过我国典型钢混结合段的试验研究现状,阐述了钢混结合段的静力学承载能力、疲劳强度、耐久性、合理构造形式以及各传力构件荷载分配关系的特征;在此基础上提出了斜拉桥钢混结合段的合理构造原则。

Steel-concrete composite bridge makes full use of the respective advantages of material performance of steel and concrete. Steel-concrete composite joint of composite beam bridge consists of steel beams, shear studs, steel strands, steel bearing plates and concrete beams. On the whole, there are mutations in the stiffness and materials of steel concrete composite joint, which may lead to more complex load transfer mechanism and construction technology as well as becoming the key issues of the research on composite beam bridge. Therefore, there is an important practical meaning to expand the applications of composite beam bridge and that is what the research of this connection form is carried out for. Since 1990s, steel-concrete composite beam bridges has developed rapidly in China; however, design methods are not sufficient enough to find out a suitable design scheme. Plenty of experimental researches on the mechanical behavior were carried out to verify the feasibility of the design structure. Research results of typical steel-concrete composite joints of composite beam bridges in China were analyzed in this paper. On this basis, characteristics such as static carrying capacity, fatigue strength, durability, reasonable structure form, and load distribution relationship of steel-concrete composite joints were discussed. Furthermore, the basic principle for reasonable structure of steel-concrete composite joints of cable-stayed bridge was proposed.