| 扁平箱梁颤振计算公式中联合折减系数的量化研究 |
| |
| 引用本文： | 廖海黎,闫雨轩,王骑,刘一枢.扁平箱梁颤振计算公式中联合折减系数的量化研究[J].中国公路学报,2019,32(1):67. |
| |
| 作者姓名： | 廖海黎 闫雨轩 王骑 刘一枢 |
| |
| 作者单位： | 1. 西南交通大学桥梁工程系, 四川成都 610031;
2. 西南交通大学风工程四川省重点实验室, 四川成都 610031 |
| |
| 基金项目： | 国家重点基础研究发展计划（“九七三”计划）项目（2013CB036301）；国家自然科学基金项目（51678508，51778547）；国家自然科学基金高铁联合基金项目（U1434205）；桥梁结构抗风技术交通行业重点实验室开放基金项目（KLWRTBMC13-04） |
| |
| 摘 要： | 扁平箱梁已广泛应用于大跨度桥梁的主梁设计中，其颤振性能通常会借助物理和数值风洞的方法获得，测试周期长、费用高。尽管采用颤振计算公式可以简便计算扁平箱梁的颤振临界风速，但当前公式中未考虑扁平箱梁气动外形和来流攻角的具体影响，计算误差较大，无法用于实际工程设计。为了提升颤振计算公式中联合折减系数的准确度，利用节段模型风洞试验开展气动外形和风攻角对扁平箱梁颤振性能影响的研究。在分析各种气动构件和外形参数对扁平箱梁颤振性能的影响后，确定以斜腹板倾角和宽高比为气动外形变量，设计制作3组12个节段模型，分别在5个风攻角下测试了有栏杆扁平箱梁的颤振性能。在此基础上，根据节段模型风洞试验获得的颤振临界风速，结合弯扭耦合颤振闭合解计算公式，量化了气动外形和风攻角变化对扁平箱梁颤振的影响，给出不同条件下扁平箱梁颤振计算公式中的联合折减系数。最后，基于实际桥梁的颤振临界风速算例，验证利用联合折减系数计算颤振临界风速的准确性和适用性。研究结果表明：在0°风攻角和正风攻角下，当扁平箱梁的宽高比分别为11，9时，斜腹板倾角的减小有利于颤振临界风速提高，宽高比为7时，斜腹板倾角对颤振临界风速没有影响；在负风攻角下，3组宽高比模型斜腹板倾角的减小均会引起扁平箱梁颤振临界风速的降低；联合折减系数与扁平箱梁截面的颤振性能正相关，可直接反映其颤振性能，相对于目前《公路桥梁抗风设计规范》中扁平箱梁颤振临界风速计算时的固定折减系数，该系数能够具体和准确反映气动外形和风攻角对扁平箱梁颤振的影响，可以结合颤振计算公式快速、准确地计算出大跨度桥梁颤振临界风速。
|
| 关 键 词： | 桥梁工程 联合折减系数 风洞试验 扁平箱梁 气动外形 颤振 |
| 收稿时间： | 2018-01-15 |
Quantification of Joint Reduction Coefficient of Flutter Closed-form Solutions for Flat Box Girders |
| |
| LIAO Hai-li,YAN Yu-xuan,WANG Qi,LIU Yi-shu.Quantification of Joint Reduction Coefficient of Flutter Closed-form Solutions for Flat Box Girders[J].China Journal of Highway and Transport,2019,32(1):67. |
| |
| Authors: | LIAO Hai-li YAN Yu-xuan WANG Qi LIU Yi-shu |
| |
| Affiliation: | 1. Department of Bridge Engineering, Southwest Jiaotong University, Chengdu 610031, Sichuan, China;
2. Wind Engineering Province Key Laboratory, Southwest Jiaotong University, Chengdu 610031, Sichuan, China |
| |
| Abstract: | Flat box girders have been widely used in the design of the main girders of long span bridges. The flutter performance of a flat box girder is usually predicted by physical methods or numerical wind tunnel model methods, which are time-intensive and involve high costs. Although the flutter onset speeds of flat box girders can be calculated by the flutter calculation method, the errors are large enough that they cannot be used in the actual engineering designs without considering the influences of aerodynamic configurations and wind attack angles. To ensure the accuracy of the flutter reduction coefficient, a study on the influence of the aerodynamic configuration and wind attack angle on the flutter performance of a flat box girder was conducted. A total of 12 sectional models were designed, and the flutter onset speeds of different sectional models with handrails were tested under 5 different wind attack angles via wind tunnel tests. Based on these observations, according to the flutter onset speed and closed-solution formula for bending-torsion, the effects of the aerodynamic configuration and wind attack angle on flutter performance are quantified by the flutter factors as the reduction coefficients; the reduction coefficients are positively correlated with flutter performance and can reflect the flutter performance directly. Finally, a case study was conducted, in which the flutter onset speeds of an actual bridge were calculated, the accuracy was verified, and the corrected joint reduction coefficients were used to predict flutter onset speeds. The results show that for 0° and positive wind attack angle and for flat box girders with side ratios of 11 and 9, the flutter onset speeds increase when the slope of the inclined web decreases. However, for the flat box girder with a side ratio of 7, the slope of the inclined web had no influence on flutter performance. For negative wind attack angles, the flutter onset speeds of the three groups of models decrease when the slope of the inclined web decreases. Compared to the fixed reduction coefficient available in the present Wind-resistant Design Specification for Highway Bridges, the reduction coefficients calculated herein can specifically reflect the influences of the aerodynamic configurations and wind attack angles on flutter performance, and the reduction coefficients can further be used to calculate acceptable flutter onset speeds quickly and accurately in conjunction with the flutter calculation formula. |
| |
| Keywords: | bridge engineering joint reduction coefficient wind tunnel test flat box girder aerodynamic configuration flutter |
| 本文献已被 CNKI 等数据库收录！ |
| 点击此处可从《中国公路学报》浏览原始摘要信息 |
|
点击此处可从《中国公路学报》下载全文 |
|
