摘要
上跨高速铁路的公路桥梁如桥面外侧布置刚度大、抗冲击性强的高防落物墙,可能显著恶化桥梁主梁气动外形.本文以跨高速铁路的两座实桥为例,借助CFD数值风洞,研究了安装2.7 m高防落物墙的扁平钢箱梁和带悬挑的混凝土矩形箱梁的气动特性,分析了防落物墙对这两种主梁风荷载和绕流特性的影响规律和机理,获得了防落物墙在风作用下的倾覆力矩系数.研究表明,防落物墙明显钝化了两种主梁气动外形,显著加大了两种主梁上表面分离区高度,导致分离流在桥面再附困难,从而明显增大了两种主梁横桥向风荷载.0°风攻角下,防落物墙的阻力占扁平钢箱主梁阻力的95%,而在-3°~3°风攻角范围,防落物墙阻力至少占矩形箱梁阻力的50%,因此,防落物墙主导了本文两种断面主梁的横桥向风荷载,但研究表明其基本不改变两种主梁的升力和扭矩系数.另外,主梁裸梁高度越小,安装防落物墙对主梁阻力系数的增加越显著;且裸梁梁高越大,安装防落物墙的主梁阻力系数也越大.
For highway bridges spanning high-speed railways,if high-rigidity and impact-resistant anti-falling object walls(AFOW)are installed on the outside of the bridge deck,the aerodynamics of the main girder may be significantly deteriorated.Taking two real bridges across high-speed railways as examples,aerodynamic investigation is conducted on flat steel box girders and concrete rectangular box girders with overhangs by using the CFD numerical wind tunnel.The influence of AFOW on wind loads and flow mechanism is analyzed.Research shows that the AFOW significantly worsens the aerodynamic shape of the main girder,remarkably increases the height of the separation zone on the leading and upper surface of the main girder,making it difficult for the separated flow to reattach on the deck surface,thus significantly increasing the transverse wind load on the main girder.At 0°wind angle of attack,the AFOW installed on the flat steel box girder contributes 95% of the main girder resistance,while in the range of-3°to 3°wind angle of attack,the AFOW installed on the rectangular box girder contributes at least 50% of drag coefficient of the main girder.The AFOW dominates the transverse wind load of two type of main girder,but basically does not change its lift and moment coefficients.The smaller the height of the bare girder of the main girder,the more significant the increase in the drag coefficient of the main girder with the AFOW.The greater the height of the bare girder,the greater the drag coefficient of the main girder installed with the AFOW.If it is necessary to install the AFOW,it is recommended to improve the aerodynamic shape of the AFOW or adopt appropriate ventilation forms to reduce the transverse wind load on the main girder.
作者
周国华
汤琴
祝志文
ZHOU Guohua;TANG Qin;ZHU Zhiwen(Hubei Transportation Planning and Design Institute,Wuhan 430051,Hubei,China;Department of Civil Engineering,Shantou University,Shantou 515063,Guangdong,China)
出处
《汕头大学学报(自然科学版)》
2026年第1期32-42,共11页
Journal of Shantou University:Natural Science Edition
基金
国家自然科学基金资助项目(52278509)。
关键词
风荷载
防落物墙
CFD
扁平箱梁
矩形箱梁
漩涡脱落
wind loads
CFD
anti-falling object walls
flat box girder
rectangular box girder
vortex shedding.
