开口肋正交异性钢桥面疲劳设计参数研究

Fatigue Design Parameters for Orthotropic Steel Decks of Single Plane Cable-Stayed Bridges

为评估重庆两江大桥单索面斜拉桥正交异性钢桥面板疲劳设计参数的合理性,对由盖板、板肋和横隔板组成的箱形正交异性钢桥面板模型进行了疲劳试验和有限元分析.基于应力等效方法,对桥面板、横隔板与纵肋三向交叉部位,进行了竖向和横向双向加载试验、等效实桥疲劳应力幅值2 000万次作用疲劳试验,在此基础上,分析了3种开孔方式、构造细节、横隔板厚度及铺装层厚度等因素对疲劳性能的影响.研究结果表明:横隔板厚度和铺装层厚度对疲劳性能的影响很大;与钥匙形和圆形相比,苹果形开孔结构的主拉应力最小,为13.7 MPa,疲劳性能最优.建议开口肋正交异性板构造横隔板厚度大于16 mm,并采用苹果形开孔方式.

Experiment and finite element analysis （FEA） were conducted on the orthotropic steel decks of two single plane cable-stayed bridges in Chongqing municipality, China, to verify the fatigue design parameters. A full scale specimen with the actual connection details of the longitudinal ribs, crossbeams and deck plates was used for fatigue test. Vertical and horizontal fatigue loads were applied to the specimen under equivalent applied stresses for 20 million cycles. FEA was done to extend the ranges of design parameters verified by fatigue tests, such as cutout shape （ apple-shaped, key-shaped and circular）, and thicknesses of plates and deck pavement. The experimental and FEA results shown that the crossbeam and pavement thickness played a significant role on fatigue performances of the orthotropic steel decks. The principal tension stress （ 13.7 MPa） near the apple-shaped cutout was the was the best in terms of fatigue performances. The plate at least 16 mm thick and the apple-shaped cutout were recommended for the crossbeam of the orthotropic steel decks.