摘要
为寻求工程经济性最优的公路悬索桥主缆垂跨比,以我国近年多座采用混凝土桥塔的单跨公路悬索桥为背景,建立主缆、锚碇、桥塔基础工程量的直接函数模型和桥塔塔身工程量的非线性函数拟合模型,对跨度750~2250 m、单层车道数4~8及双层车道数6+4、垂跨比1/14~1/6共952种布置形式的悬索桥进行大范围关于主缆垂跨比的工程经济性研究,并以2座实桥为算例分析主缆垂跨比对悬索桥静、动力性能及抗风性能的影响。结果表明:主缆垂跨比对悬索桥工程经济性影响显著;悬索桥主缆最优垂跨比与跨度相关,而车道数、加劲梁荷载集度的影响相对较小,涉水和不涉水的差异也不显著;基于工程经济性考虑,跨度750~2250 m的悬索桥主缆最优垂跨比为1/6.5~1/8.5,比经验值增大较多。2座实桥算例分析表明随着垂跨比增加,加劲梁挠度和活载应力有所增加,抗风性能略有提升,建议方案设计阶段加大垂跨比研究范围、对工程经济性和桥梁力学性能进行综合比选。
This study focuses on the selection of sag-to-span ratio of main cables for the highway suspension bridge that will bring maximum economic benefits.Multiple highway suspension bridges featuring concrete towers and single suspended spans in China were surveyed.Direct function models of engineering quantity of main cables,anchorages,and foundations as well as a nonlinear function fitting model of the engineering quantity of the concrete towers were established,by which suspension bridges of 952 structural configurations were collected to investigate the relationship between the sag-to-span ratio of main cables and engineering economy.The 952 structural configurations were statistically categorized in accordance with the span lengths(between 750 mm and 2250 m),vehicle lanes layout(4 to 8 lanes on a single deck and 6+4 lanes of a double decker),and sag-to-span ratios(between 1/14 and 1/6).Two existing bridges were selected to analyze the influence of the sag-to-span ratio on the static and dynamic properties as well as wind resistance of suspension bridges.It is shown that the sag-to-span ratio of main cables is closely related to the engineering economy of a suspension bridge.Span length is a critical factor in the sag-to-span ratio of main cables of a suspension bridge,the influences of lane amount and load concentrations of the stiffening girder are relatively minor,and no obvious difference is found between the bridge having in-water components and the bridge having no in-water components.For the suspension bridges with main span lengths between 750 m and 2250 m,the optimal sag-to-span ratios of the main cables should be between 1/6.5 and 1/8.5,much larger than the empirical values.As per the analysis of the two real bridges,increasing the sag-to-span ratio will lead to the increase of the deflection and live-load-induced stresses in the stiffening girder,and the enhancement of the wind resistance as well.It is suggested to enlarge the scope of the sag-to-span ratio study at the preliminary design stage and comprehensively compare the engineering economy and mechanical property of the bridge.
作者
彭元诚
丁少凌
彭健哲
PENG Yuancheng;DING Shaoling;PENG Jianzhe(CCCC Second Highway Consultants Co.,Ltd.,Wuhan 430056,China;Shanghai Jiao Tong University,Shanghai 200240,China)
出处
《桥梁建设》
EI
CSCD
北大核心
2024年第5期22-29,共8页
Bridge Construction
基金
2021中国交通建设集团重大研发项目(2021-ZJKJ-08)。
关键词
悬索桥
主缆垂跨比
工程量模型
工程经济性
力学性能
桥梁设计
suspension bridge
sag-to-span ratio of main cable
engineering quantity model
engineering economy
mechanical property
bridge design
作者简介
彭元诚,教授级高工,E-mail:1059812508@qq.com。研究方向:桥梁设计理论,不同垂度四主缆悬索桥、空腹式连续刚构桥等新型桥梁结构体系。
