关键词: 桥梁工程；AS法悬索桥；主缆；鞍座；滑移试验；隔板厚度；基础摩擦系数

Abstract: For suspension bridges constructed by AS method, the number of single strand steel wires is much more than that of PPWS method, the cable saddle groove is much wider than that of PPWS method, and the thickness of diaphragm between notches is also increased to 10 mm. Yangbaoshan suspension bridge on Gui-Huang expressway is a long-span suspension bridge constructed by using AS method to erect main cable for the first time in China. In order to clarify the sliding mechanism between the main cable and the cable saddle and verify the anti-sliding reliability, the influence of each contact surface in the saddle groove on the anti-sliding coefficient was studied through experiments, taking Yangbaoshan suspension bridge as the background. Results show that the cable strands in the saddle groove slide layer by layer, and the sliding sequence is always from the upper cable strand to the lower cable strand. The nominal friction coefficient increases progressively from the upper cable strands to the lower cable strands. Different contact states of the main cable steel wire in the saddle groove correspond to different foundation friction coefficients. The foundation friction coefficients of cable strand and groove bottom, cable strand and side wall, cable strand and diaphragm and cable strand and cable strand are 0.25, 0.35, 0.25 (5 mm diaphragm), 0.3 (10 mm diaphragm) and 0.21 respectively. Increasing the thickness of saddle groove diaphragm can effectively increase the structural stiffness, improve the foundation friction coefficient and improve the overall anti-sliding performance of saddle groove. It is suggested that the value of friction coefficient between the main cable and saddle in AS method suspension bridges should be 0.2.

Key words: bridge engineering; AS method suspension bridge; main cable; saddle; slip test; diaphragm thickness; basic friction coefficient