摘要
拉吊索是缆索桥梁的主要承重构件,索力是反映拉吊索和缆索桥梁整体受力状态的重要参数。目前在实际工程中缆索桥梁短索索力的准确评估仍是一个难题,且如何界定短索也未得到有效解决。针对实际工程中刚度对索力的影响及短索的确定等问题,以现行规范中大跨度桥梁平行钢丝拉索为对象,分析了索长、长细比和拉索特征参数ξ等对拉索刚度和索力的影响。根据实际工程情况,以拉索刚度影响系数5%为限,提出了短索的判断准则。分析了不同钢丝直径规格条件下,拉索刚度影响系数随拉索长细比和ξ的变化规律。结果表明:随着索长、长细比和ξ的逐步增大,拉索抗弯刚度对索力的影响均逐渐减小;当拉索两端铰接,且索长小于6.5 m时,刚度对索力的贡献大于5%;当拉索两端固结,且索长小于11 m时,刚度对索力的贡献大于5%;拉索刚度影响系数与钢丝直径无关,且不直接取决于拉索直径。根据短索的判断准则,给出了短索的索长、长细比与ξ等参数的取值范围,并建议将现行规范中大跨度桥梁平行钢丝拉索长度小于11 m时确定为“短索”,如果以长细比来进行判断,则长细比小于175时为短索,以ξ值判断时,ξ值小于23时为短索。对于实桥测试计算,为方便工程人员使用,建议以索长来判断短索。
Cable is the main load-bearing component of cable-supported bridge,and the cable force is an important parameter reflecting the overall stress state of cable and cable-supported bridges.At present,the accurate evaluation of short cable force in cable-supported bridges is still a challenge in practical engineering,and how to define short cables has not been effectively solved.In view of the problems such as the influence of stiffness on cable force and the determination of short cable in practical engineering,taking the parallel steel wire cables of long-span bridges in current specifications for the object,the influences of cable length,slenderness ratio and cable characteristic parameterξon the cable stiffness and cable force are analyzed.Based on the actual engineering situation,the judgment criterion for short cables is proposed with a limit of 5%for the influence coefficient of cable stiffness.The variations of the influence coefficient of cable stiffness with the slenderness ratio andξunder different wire diameter specifications are analysed.The result shows that(1)with the increase of cable length,slenderness ratio andξ,the influence of cable bending stiffness on cable strength decreases gradually;(2)when both ends of the cable are hinged and the cable length is less than 6.5 m,the contribution of stiffness to the cable force is greater than 5%;(3)when both ends of the cable are fixed and the cable length is less than 11 m,the contribution of stiffness to the cable force is greater than 5%;(4)the influence coefficient of cable stiffness has nothing to do with wire diameter,and does not directly depend on the cable diameter.Based on the judgment criterion for short cables,the value ranges of the parameters such as cable length,slenderness ratio andξof short cables are proposed,and it is recommended to define the parallel steel wire cables with length of less than 11 meters for long-span bridges in the current specifications as“short cables”.If judging by slenderness ratio,the cables with the slendern
作者
樊平
刘刚
姜维
张劲泉
FAN Ping;LIU Gang;JIANG Wei;ZHANG Jin-quan(Research institute of Highway,Ministry of Transport,Beijing 100088,China)
出处
《公路交通科技》
CSCD
北大核心
2023年第6期113-118,125,共7页
Journal of Highway and Transportation Research and Development
基金
中央公益性科研院所基本科研业务费项目(2021-9006a)
中央公益性科研院所基本科研业务费项目(2021-9006b)
桥梁结构安全技术国家工程实验室开放课题项目(2019-GJXFXT)。
关键词
桥梁工程
抗弯刚度影响
索力影响因素分析
短索
拉索
bridge engineering
influence of flexural stiffness
analysis of influence factors of cable force
short cable
parallelwire cable
