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研究斜拉桥索塔U形预应力束力学性能是避免索塔开裂的重要工程措施。采用在U形预应力束张拉时,固定端工作锚不设置夹片,在工具锚和千斤顶之间设置高精度穿心式压力传感器,张拉端按照正常设计进行预应力锚垫板、锚具安装的方法,该文开展了测试U形预应力束摩阻损失的现场试验研究。分析了U形筋预应力损失的影响因素,推导了弯曲处钢束对边壁的挤压引起预应力损失的计算公式,实测了U形预应力束的孔道摩阻系数以及摩阻损失率,得到了针对索塔U形预应力束孔道摩阻系数的取值。
Studying the mechanical properties of U-shaped prestressing beam of cable-stayed bridge is an important engineering measure to avoid the cracking of the tower. When U-shaped prestressing strands are used for tensioning, the working anchor at the fixed end is not provided with clips, and a high-precision through-core pressure sensor is arranged between the tool anchor and the jacking. The tensioning end is under the normal design of the prestressed anchor plate, the anchor With the installation method, this paper carried out a field test to test the friction loss of U-shaped prestressed beam. The influencing factors of the prestress loss of U-shaped tendons are analyzed. The formula for calculating the prestress loss caused by the extrusion of the steel beam at the bend is deduced. The friction coefficient and friction loss of the U-shaped prestressed beam are measured. The value of the frictional coefficient of the U-shaped prestressed beam hole is obtained.