开封黄河大桥斜拉索新型索鞍力学性能研究

Study of Mechanical Behavior of New Type Saddles for Stay Cables of Kaifeng Huanghe River Bridge

开封黄河大桥主桥为预应力混凝土多跨部分斜拉桥,斜拉索采用环氧涂层填充型钢绞线。采用HDPE分丝管索鞍,即将HDPE分丝管置于矩形焊接钢箱内,在分丝管外灌注高标号水泥浆的结构形式。为验证该鞍座结构受力的合理性及结构的可靠性,应用有限元法对其进行数值仿真分析,对足尺模型的单根及整束钢绞线进行摩阻力试验,测试钢绞线与HDPE管之间的摩阻力,并对鞍座结构进行抗压性能试验。结果表明,钢绞线与HDPE管之间的摩阻力能够抵抗施工和运营阶段索鞍两侧的不平衡索力;鞍座内部水泥灌浆料密实,无任何裂纹和压碎现象,鞍座结构满足受力要求;索鞍结构完好,内部水泥浆基本处于弹性工作范围。

The main bridge of Kaifeng Huanghe River Bridge is a prestressed concrete multispan extradosed bridge. The stay cables of the bridge are made up of the epoxy-coated steel wire strands and are arranged in the cable saddles with HDPE （high-density polyethylene） sleeves. The cable saddle is a structure with its HDPE sleeves installed in a rectangular steel box and with the high-grade cement mortar grouted outside the sleeves. To verify the rationality of the force conditions and the reliability of the saddle, the finite element method was used to conduct the nu- merical simulation analysis, the frictional resistance test was made for a single wire strand and a full-scale model entire stay cable, the resistance between the wire strand and HDPE sleeve was measured and the compressive test for the saddle was also made. The results of the tests indicate that the frictional resistance can resist the unbalanced force of a stay cable at both sides of a pylon at the stage of construction and operation, the cement mortar grouted in the cable saddle is dense without cracking and breaking, the saddle satisfies the designed force conditions and the cement mortar thereof basically works in the elastic range.