扭背索斜拉桥非对称索塔锚固区足尺模型试验研究  

Study of Full-Scale Model Test for Asymmetric Anchor Zone in Pylon of Cable-Stayed Bridge with Twist Plane Back Stays

作　　者：钟继卫[1,2] 黄展军 王波[1,2] 何祖发[1,2] 

机构地区：[1]中铁大桥局集团桥科院有限公司,湖北武汉430034 [2]桥梁结构安全与健康湖北省重点实验室,湖北武汉430034 [3]南昌市政建设投资发展有限公司,江西南昌330038

出　　处：《世界桥梁》2011年第4期45-48,共4页World Bridges

摘　　要：扭背索索塔锚固区因扭面背索编排方式而呈非对称结构,边、中跨方向承受非对称荷载,且环向预应力筋采用非对称布索方式。为探讨非对称预应力混凝土索塔锚固区的预应力作用效应、承载能力及抗裂性,采用有限元法对足尺节段模型试验研究过程进行理论计算分析。结果表明:环向预应力钢束实测张拉伸长量为理论值的1.2倍,考虑其"贴壁效应"后,实测值与等效理论值基本吻合;由于结构的整体非对称性,模型加载后的裂纹位置、裂纹扩展趋势等呈现明显的非对称性。该研究成果可以指导扭背索索塔锚固区的设计与施工。Owing to the arrangement way of twist plane back stays, the anchor zone in pylon of cable-stayed bridge for the back stays is an asymmetric structure that will bear asymmetric load from side span and central span and the arrangement of the loop prestressing strands for the anchor zone is asymmetric as well. To study the prestressing effect, bearing capacity and cracking resistance of the asymmetric anchor zone structure in a prestressed concrete pylon of cable-stayed bridge, the full-scale sectional model test was made and the finite element method was used to cal- culate and analyze the process of the test. The results of the calculation and analysis indicate that the measured elongation value of the tensioned loop prestressing strands is 1.2 times of the theoretic value. The two values are basically agreeable when the effect of pressing of the strands against duct wall is taken into account. Because of the integral asymmetry of the structure, the locations and propagation tendency of cracking in the structure after the model is loaded exhibit obvious asymmetry. The results of the study herewith may serve as guidance to the design and construction of the anchor zones in pylons for twist plane back stays.

关 键 词：斜拉桥 南昌英雄大桥 索塔锚固区 模型试验 有限元法 抗裂性 

分 类 号：U448.27[建筑科学—桥梁与隧道工程]