Degradation mechanism of simply supported steelconcrete compositebox girder under tanker fire condition(PDF)
长安大学学报（自然科学版）[ISSN:1006-6977/CN:61-1281/TN]
- Issue:
- 2018年06期
- Page:
- 31-39
- Research Field:
- 桥梁与隧道工程
- Publishing date:
Info
- Title:
- Degradation mechanism of simply supported steelconcrete compositebox girder under tanker fire condition
- Author(s):
- ZHANG Gang1; ZONG Ruhuan1; 2; HUANG Qiao3; YAO Weifa3; CHENG Huacai
- （1. School of Highway, Changan University, Xian 710064, Shaanxi, China; 2. Ningxia Highway Survey andDesign Institute Co., Ltd., Yinchuan 750011, Ningxia, China； 3. School of Transportation,Southeast University, Nanjing 210096, Jiangsu, China； 4. Anhui Highway Test andResearch Center Co. Ltd.， Hefei 230601， Anhui， China）
- Keywords:
- bridge engineering; steelconcrete composite box girder; FEM; flexural capacity; fire; degradation mechanism
- PACS:
- -
- DOI:
- -
- Abstract:
- Aimed at ultimate failure of simply supported steelconcrete composite box girder caused by the oil tanker fire, the difference between bridge fire and building fire was given, the numerical calculation method of the whole fire process of thermomechanical coupled and the equivalent calculation method of strength division was provided, according to the fire resistance of simply supported steelconcrete composite box girders. The temperature distributed within the girder section under HC fire was analyzed, and the degradation process of the strength in each component was studied. Further, the timedependent variation relationship between the crosssectional flexural capacity and fire exposure time of a simply supported steelconcrete composite box girder was analyzed. A formula predicting the flexural capacity with time of HC fire was derived. The failure time of a composite box bridge girder under a HC fire condition was obtained by comparing the flexural capacity and load effect. The results show that the provided method can predict the temperature and structural responses of a composite box bridge girder under HC fire conditions. The average temperature can be highly influenced by the thickness of each component. The peak temperature in the girder section without a transverse diaphragm is higher than that in girder section with a transverse diaphragm. The flexural capacity of the midspan section of simply supported steel and concrete composite box girder can be grouped into four stages with HC fire. The flexural capacity remains in the initial state for up to 8 min, the rate of degradation becomes larger between 8 to 16 min, the neutral axis feature of section changed from 16 to 48 min, then it steps into faster degradation and fails after 48 min. The extinguishing time is suggested to be limited to 8 min. The timedependent decay formula proposed to solve the flexural capacity of the cross section of a simply supported steelconcrete composite box girder is simple, The decay mechanism of the flexural capacity of simply supported steelconcrete composite box girder is further clarified, and it can provide data to guide fire resistance design and intelligent assessment after fires.
Last Update: 2018-12-18