曲弦下承式钢管混凝土桁梁桥加固方案研究  

Study of Retrofit Schemes to Concrete-Filled Steel Tubular Bowstring Truss Girder Bridge

作　　者：王艳[1] 陈淮[1] 李杰[1] 陈代海[1] 

机构地区：[1]郑州大学土木工程学院,河南郑州450001

出　　处：《世界桥梁》2015年第5期74-79,共6页World Bridges

摘　　要：郑州市北三环路彩虹桥为(122+62+62+122)m简支曲弦下承式钢管混凝土桁梁桥,为改善其目前运营服务能力,提出6种加固改造方案,针对各加固方案进行仿真计算分析。计算结果表明:简支变连续体系改造使主桁端部出现应力集中现象,不适用于该桥改造;在改造横撑的基础上增设跨中吊杆是减小横梁跨中相对变形的有效途径;增设边纵梁和外吊杆可有效改善横梁悬臂端变形,提升悬臂段桥面承载力;增大腹杆截面可明显提高62m跨径桥梁的整体刚度和横梁局部刚度,有效降低腹杆的应力幅;加强纵向预应力可有效降低桥梁的下弦杆变形,但对横梁相对变形影响不大。综合运用横撑改造、增设跨中吊杆和外吊杆、增大腹杆面积、加强下弦杆纵向预应力等几种改造措施使桥面变形明显改善,62m跨径桥梁整体结构刚度得到有效提高,腹杆最大应力显著降低,上弦杆最大应力仍有足够的安全储备。The Rainbow Bridge on the North Third Ring Road in Zhengzhou is a simply-supported concrete-filled steel tubular bowstring truss girder bridge with span arrangement of（122＋62＋62＋122）m.To improve the current operation and service ability of the bridge,6retrofit schemes were proposed,and simulation calculation analyses were conducted in accordance with the contents of each scheme.Results of the calculation indicate that the retrofit scheme of transforming the simply-supported structure to a continuous system is not feasible to this bridge,because stress concentration might occur at the ends of the main truss.An effective way to reduce the relative deformation in the midspan of the cross beam of the bridge is to add midspan hangers on the basis of cross beam retrofit.The addition of side stringers and external hangers can effectively reduce the cantilever end deformation of the cross beam and improve the load bearing capacity of the deck in the cantilever section.The increase of the cross section of web members can remarkably improve the overall stiffness of the 62 mspan bridge and the local stiffness of the cross beam,and effectively reduce the stress range of web members.The strengthening of the longitudinal prestress can effectively prevent the deformation of the lower chords,but shows subtle influence on the relative deformation of cross beams.The bridge deck deformation has been noticeably rectified by the combined use of lateral bracing retrofit,adding midspan hangers and external hangers,increasing the cross section of web members,and strengthening the longitudinal prestress of lower chords.The overall structural stiffness of the 62 mspan bridge has been effectively improved,and the maximum stress in the web members are considerably deceased,and the maximum stress of the upper chords still has enough safety margin.

关 键 词：钢管混凝土桥 曲弦桁梁桥 加固 仿真分析 横撑 吊杆 腹杆 弦杆 

分 类 号：U445.72[建筑科学—桥梁与隧道工程]