Bearing capacity of PC box girder based on concrete spallingunder fuel tanker fire exposure(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:
- 79-88
- Research Field:
- 桥梁与隧道工程
- Publishing date:
Info
- Title:
- Bearing capacity of PC box girder based on concrete spallingunder fuel tanker fire exposure
- Author(s):
- ZHANG Gang; HOU Zhangwei; SONG Chaojie; HE Shuanhai; LI Yuan
- (School of Highway, Changan University, Xian 710064, Shaanxi, China)
- Keywords:
- bridge engineering; PC; FEM; fire; spalling; temperature; flexural capacity
- PACS:
- -
- DOI:
- -
- Abstract:
- Aiming at the damage characteristics of prestressed concrete bridge caused by oil tanker fire， a prestressed concrete (PC) box girder, which is widely applied in bridge construction, was selected as the research object, and a threegrade index of concrete spalling at elevated temperature was proposed. The concrete spalling conditions under hydrocarbon fire scenarios were defined, and the birthdeath element technique was applied to simulate the concrete spalling. The complete distribution profile of the crosssectional temperature within the PC box girder considering concrete spalling was analyzed. The ultimate flexural capacity of the PC box girder under different spalling indices was calculated, and the calculation formula was proposed. The results show that the temperature curve of key points in the cross section has a threestage rise. The concrete spalling can lead to a sudden change of crosssectional temperature, and the temperature shows a layer distribution toward the inside of the cross section after concrete spalling. The strength of the prestressed strand and reinforcement decreased significantly as a result of concrete spalling. With a larger depth of concrete spalling, the flexural capacity decreased with a faster step. When severe spalling of concrete occurred at 180 min, the flexural capacity of a PC box girder at midspan decreased from 60.73% to 14.87%, and the flexural capacity of the PC box girder at L/4 section (L is the span) decreased from 64.37% to 19.37%. Flexural capacity demonstrated a multistage descent at different depths of concrete spalling. Concrete spalling has a significant effect on the flexural capacity and temperature distribution of PC box girders. The proposed formula considering concrete spalling is simple and practical, and it can be used to evaluate the fire resistance of the PC box girder. 4 tabs, 10 figs, 26 refs.
Last Update: 2018-12-18