Fatigue characteristics of steel box girder based on measured vehicle flow(PDF)
长安大学学报（自然科学版）[ISSN:1006-6977/CN:61-1281/TN]
- Issue:
- 2019年05期
- Page:
- 48-58
- Research Field:
- 桥梁与隧道工程
- Publishing date:
Info
- Title:
- Fatigue characteristics of steel box girder based on measured vehicle flow
- Author(s):
- LI Chuanxi; LI You; CHEN Zhuoyi; HE Jun; LIU Yiming
- (1.School of Civil Engineering, Changsha University of Science & Technology, Changsha 410114, Hunan, China; 2. Key Laboratory of Safety Control for Bridge Engineering of the Ministry of Education, Changsha University of Science & Technology, Changsha 410114, Hunan, China)
- Keywords:
- bridge engineering; vehicle load spectrum; model test; arc incision of transverse diaphragm; fatigue life; crack propagation
- PACS:
- -
- DOI:
- -
- Abstract:
- To study the fatigue properties of the base material at the arc incision of a steel box girder under traffic load, Foshan Pingsheng Bridge was used for the engineering background, and based on the monitoring data of the weighinmotion (WIM) system, the fatigue load spectrum of nine vehicle types of the bridge was obtained. A steel box girder segment model was established using ABAQUS, and the fatigue stress history curve of the arc incision of the transverse diaphragm was calculated. Validated by model tests, the fatigue life and crack propagation law of the design arc incision was obtained. The results show that the fatigue model of the suspension bridge can be simplified to V2 to V10, the axle weights of the same model vary in different lanes, the axle weights of lanes 3# and 4# are generally higher than lanes 1#, 2#, 5#, and the Z3 axis of the V10 model in lane 3# has a maximum axle weight of 151 kN. The proportions of V2 to V10 models in heavy traffic lanes (lanes 3# and 4# ) are significantly higher than in other lanes. The influence lines along the longitudinal bridge at the arc incision under the axles are shorter, about the spacing of the three diaphragms. The dynamic response is always compressive, and only the axis group can be identified. The weight of a single axle in the axis group cannot be distinguished when the rear axle group of the V10 model passes, and the compressive stress amplitude of the arc incision slit reaches a maximum of -169 MPa. When considering the vehicle overload, the minimum and maximum fatigue stress amplitudes at the arc incision are 1.17 and 1.75 times of that without vehicle overload, respectively. Under the action of the film compressive stress amplitude, the fatigue crack occurred in the base material at the arc incision of the model test piece, and the cracking position is consistent with the real bridge, and cracks both appeared near the arcing point of the arc incision of the diaphragm, and the length of the crack was 53 mm. The rate of crack propagation is faster in the early stage and gradually slowing down in the later stage. The lateral position of the wheel load has a significant influence on the stress amplitude at the arc incision. When the wheel load acts directly above the arc incision, the stress amplitude at this position is the largest. 3 tabs, 14 figs, 33 refs.
Last Update: 2019-10-16