Abstract: Aiming at the problem of influence of cast-in-situ sectional length on the stress of horizontal swivel cable-stayed bridges, field measurement and theoretical analysis were combined to analyze the difference of the influence of different segment lengths on the stress and the displacement of the both horizontal swivel continuous beam bridges and horizontal swivel cable-stayed bridges. The mechanism of friction and bond between cast-in-situ beam and formwork was illustrated,and the range of friction coefficients was pointed out. The influence of structural system transformation on the stress state of horizontal swivel cable-stayed bridges was studied, and the contribution of three factors, namely, the length of cast-in-situ segment, the design of prestressed tendon and the effect of friction and bond to the stress state of the structure was revealed. The research results show that different segment lengths have less influence on the forces of the horizontal swivel continuous beam bridge and horizontal swivel cable-stayed bridge, and the results of the two are similar, but the influence on the displacement is greater, and the two results are opposite. The friction-bond effect between cast-in-situ beam and formwork cannot be neglected, which has considerable impact on the stress and deformation of the main beam.The friction coefficient between cast-in-situ beam and formwork is between 0.26 and 0.33. With the increase of friction coefficient,the horizontal displacement and the upper edge compressive stress of the main girder decrease gradually,while the vertical displacement, the lower edge compressive stress, the displacement of the tower top and the cable force increase gradually.The friction-bond effect contributes the most to the force of the structure,which has greater influence on the stress and displacement of the structure;and the cast-in-situ segment length is the second,which has only affected the displacement greatly.Furthermore,the contribution of the design of prestressed tendon is the least, which has little influence on both the structure stress and displacement.

Key words: bridge engineering, swivel cable-stayed bridge, cast-in-situ segment length, friction bond resistance, friction coefficient, prestressed steel design

摘要： 针对现浇分段长度对平转斜拉桥受力的影响问题，采用现场实测和理论分析相结合的方法，分析不同分段长度对平转连续梁桥和平转斜拉桥结构受力、位移的影响差异，说明现浇梁和模板的摩擦黏结机理，指出摩擦系数的取值范围，研究结构体系转换对平转斜拉桥受力状态的影响，揭示现浇分段长度、预应力筋设计和摩擦黏结效应这3种因素对结构受力的贡献大小。研究结果表明：不同分段长度对平转连续梁桥和平转斜拉桥的结构受力影响较小、两者结果类似，对位移影响较大、两者结果相反；现浇梁和模板存在摩擦黏结效应，此效应对主梁变形、受力影响显著，不可忽略；现浇梁和模板摩擦系数介于0.26~0.33之间，随着摩擦系数逐渐增大，主梁水平位移和上缘压应力逐渐减小，主梁竖向位移、下缘压应力、塔顶位移和拉索力逐渐增大；摩擦黏结效应对结构贡献最大，对结构受力、位移均有较大影响；现浇分段长度次之，仅对位移存在较大影响；预应力筋设计贡献最小，对结构受力、位移影响均很小。

关键词: 桥梁工程, 转体斜拉桥, 现浇分段长度, 摩擦黏结阻力, 摩擦系数, 预应力筋设计