Analysis on influence of initial bending stress on bearing capacity of reinforced concrete beam after freezethaw carbonization(PDF)
长安大学学报（自然科学版）[ISSN:1006-6977/CN:61-1281/TN]
- Issue:
- 2020年5期
- Page:
- 38-47
- Research Field:
- 桥梁与隧道工程
- Publishing date:
Info
- Title:
- Analysis on influence of initial bending stress on bearing capacity of reinforced concrete beam after freezethaw carbonization
- Author(s):
- HU Dalin; XU Huaicun; ZHANG Hang; CHEN Feng; ZHA Bin
- 1. School of Highway, Changan University, Xian 710064, Shaanxi, China; 2. CCCC First HighwayConsultants Company Limited, Xian 710075, Shaanxi, China; 3. State Key Laboratory ofSafety and Health for Inservice Long Span Bridges, Nanjing 211112, Jiangsu, China
- Keywords:
- bridge engineering; bearing capacity; load test; reinforced concrete beam; bending stress; finite element simulation
- PACS:
- -
- DOI:
- -
- Abstract:
- In order to research the influence of bending stress on the bearing capacity of existing reinforced concrete bridges under the interaction of freezethaw and carbonization, 8 reinforced concrete beams were designed and made, bending stress of the test beams was loaded with a selfdesigned load holding device, the test beams were placed in the environmental laboratory for freezethaw carbonization coupling corrosion, then load test was carried out on the test beams after the corrosion. The fracture analysis, strain characteristic analysis and bearing capacity of test beams at different bending stress levels were studied. The finite element numerical model of the reinforced concrete test beam was established, and analysis results were compared with that of experiment. The results show that with the increase of initial bending stress level of the two groups of test beams, the failure pattern of the test beams will change from one main crack to multiple cracks, ductility of the test beam is significantly reduced. The compressive strain slope and tensile strain values of the midspan will gradually increase， the midspan strain distribution no longer fully conforms to plane crosssection assumption. By analyzing the loaddisplacement curve of the test beam, when increase of concrete strength grade, the ability of the test beam to resist corrosion of carbonization and freezethaw improves significantly. As the bending stress level increases, the bearing capacity (yield bending moment, ultimate bending moment) of the test beams will decrease and will be approximately linear. Through the comparative analysis between ANSYS finite element numerical simulation and the measured data of bearing capacity of the test beams, modified coefficient φ of the constitutive behaviors of reinforced concrete beams under different bending stress levels after the interaction of freezethaw and carbonization is concluded. The results of the test and numerical analysis can provide a reference and a simplified analysis method for the bearing capacity analysis and evaluation of the reinforced concrete bridges servicing in the cold zone. 5 tabs, 13 figs, 32 refs.
Last Update: 2020-10-12