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Analysis on influence of initial bending stress on bearing capacity of reinforced concrete beam after freezethaw carbonization(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 freezethaw carbonization
Author(s):
HU Dalin XU Huaicun ZHANG Hang CHEN Feng ZHA Bin
1. School of Highway, Changan University, Xian 710064, Shaanxi, China; 2. CCCC First HighwayConsultants Company Limited, Xian 710075, Shaanxi, China; 3. State Key Laboratory ofSafety 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:
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DOI:
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Abstract:
In order to research the influence of bending stress on the bearing capacity of existing reinforced concrete bridges under the interaction of freezethaw and carbonization, 8 reinforced concrete beams were designed and made, bending stress of the test beams was loaded with a selfdesigned load holding device, the test beams were placed in the environmental laboratory for freezethaw 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 midspan will gradually increase, the midspan strain distribution no longer fully conforms to plane crosssection assumption. By analyzing the loaddisplacement curve of the test beam, when increase of concrete strength grade, the ability of the test beam to resist corrosion of carbonization and freezethaw 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 freezethaw 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.

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Last Update: 2020-10-12