摘要
以长沙市香炉洲大桥东汊航道桥为工程背景,创新地提出加肋大悬臂宽幅箱梁结构,在加劲肋位置箱室内部设半横隔板,并在加劲肋及半横隔板内设置预应力,桥面板横向预应力采用弯束交错布置。基于横向框架模型,对比分析宽幅箱梁不同横向预应力束布置形式下的应力分布。为了验证横框模型在加肋大悬臂宽幅箱梁中的适用性,对加肋大悬臂箱梁实体与横框计算应力进行了对比。结果表明:宽幅箱梁桥面板横向预应力采用弯束交错布置相较直束布置可有效改善应力分布,降低应力峰值;加肋大悬臂箱梁桥面板及横肋的预压应力可有效消减拉应力,改善箱梁运营状态;恒载作用下,加肋大悬臂箱梁顶板上缘受力较均匀,下缘受力不均匀,横向框架模型桥面板上缘应力较实体模型偏大0.64 MPa,差值最大值出现在中箱室的跨中位置,约为实体模型应力值的13%。活载作用下,加肋大悬臂箱梁局部受力,车辆荷载由多个梁肋承担,横向框架模型应力与实体模型应力相差较大。恒载作用下,横向框架模型计算结果满足工程精度要求,设计实践中,可先根据横向框架模型初步确定结构构造及横向预应力钢束线型,再采用实体模型校核结构局部受力。研究成果可为类似工程的设计提供有益参考。
The east shipping channel bridge of Xiangluzhou bridge in Changsha is taken as the engineering background,the ribbed and long cantilever wide box girder structure is innovatively proposed,the semi-diaphragm is set inside the box chamber at the rib position,and the transverse prestress is set inside the rib and the semi-diaphragm,the transverse prestressed steel strand of the bridge deck is arranged by staggered bending beams.Based on the cross-frame finite element model,the stress distribution of wide box girder under different transverse prestressed steel strand arrangement is compared and analyzed.In order to verify the applicability of the cross-frame model in the ribbed and long cantilever wide box girder,the solid model stress of ribbed and long cantilever box girder is compared with the cross-frame model stress.The results show that the transverse prestressing of the wide box girder bridge deck using a staggered arrangement of bent beams can effectively improve stress distribution and reduce stress peaks compared to a straight beam arrangement;the transverse pre-compression stress of the deck and ribs of the ribbed and long cantilever wide box girder can effectively reduce the tensile stress,which can improve the operation status of the box girder;under the action of dead load,the upper edge of the ribbed and long cantilever box girder is uniformly stressed,and the lower edge is unevenly stressed,the upper edge stress of the transverse frame model bridge deck is 0.64 MPa higher than that of the solid model,and the maximum difference occurs at the mid span position of the middle box chamber,which is about 13%of the stress value of the solid model.Under the action of live load,the locally stressed cantilever box girder with added ribs bears the vehicle load from multiple beam ribs,resulting in a significant difference in stress between the transverse frame model and the solid model.Under the action of dead load,the results of the cross frame model can meet the requirement of engineering precision,in the design practice,the structural dimension and the transverse prestressed steel strand shape can be preliminarily determined according to the cross-frame model,and then the solid model is used to check the local stress of the structure.The research results can provide a useful reference for the design of ribbed and long cantilever wide box girder.
作者
龙绿军
张晋瑞
盖永斌
乔秋衡
刘勇
卢立志
LONG Lyujun;ZHANG Jinrui;GAI Yongbin;QIAO Qiuheng;LIU Yong;LU Lizhi(Hunan Provincial Communications Planning,Survey&Design Institute Co.,Ltd.,Changsha,Hunan 410200,China;School of Civil Engineering,Central South University,Changsha,Hunan 410075,China)
出处
《公路工程》
2025年第3期126-132,172,共8页
Highway Engineering
基金
湖南省交通科技项目(202404)。
关键词
加肋大悬臂
宽幅箱梁
半横隔板
预应力钢束线形
横向应力
ribbed and long cantilever
wide box girder
semi-diaphragm
prestressed steel strand shape
transverse stress
