悬索桥AS法主缆索鞍抗滑移试验研究

Cable-Saddle Anti-slipping Test of AS Method Suspension Bridges

AS法施工的悬索桥,单根索股钢丝数远大于PPWS法,索鞍槽路比PPWS法宽很多,槽口间隔板的厚度也增至10 mm。贵黄高速公路上的阳宝山特大桥是国内首次采用AS法架设主缆建造的大跨度悬索桥,为明确AS法索鞍内主缆与索鞍间的滑移机理,验证抗滑可靠性,以阳宝山特大桥为背景,通过试验研究了鞍槽内各接触面对抗滑移系数的影响。结果表明:鞍槽中的索股是分层逐个滑移的,滑移顺序总是从上层索股到下层索股;名义摩擦系数从上层索股到下层索股依次递增;主缆钢丝在鞍槽中不同的接触状态对应不同的基础摩擦系数,索股与槽底、索股与侧壁、索股与隔板以及索股与索股的基础摩擦系数分别为0.25、0.35、0.25(5 mm隔板)、0.3(10 mm隔板)和0.21,增大鞍槽隔板厚度可有效增大结构刚度提高基础摩擦系数,提高鞍槽整体抗滑性能;建议AS法悬索桥主缆与索鞍间的摩擦系数可以取为0.2。

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.