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Study on the Pattern of Temperature Propagation of Reinforced Concrete Structure under High-Temperature Environment
(1 School of Civil Engineering, Architecture and Environment, Xihua University, Chengdu 610039; 2 China Railway 23rd Construction Bureau Group Architectural Design Institute Co., Ltd., Chengdu 610031)
Abstract The mechanical properties of reinforced concrete structures under high-temperature environment will be reduced to different degrees, seriously affecting the service life of the structures, however the temperature distribution pattern within the reinforced concrete structures is the basis for the analysis of the fire resistance of the components as well as for repair and reinforcement. In view of this, this paper carries out the indoor fire test to study the temperature propagation pattern within reinforced concrete structures under high-temperature environment based on the actual condition of the reinforced concrete lining of a prefabricated tunnel project in Chengdu. According to the indoor test results, this paper uses the numerical simulation method to optimize the concrete-related thermal parameters and obtains numerical simulation parameters more suitable for actual project condition, and also conducts a thermal coupling analysis on the prefabricated tunnel. The study results show that: (1) under single-sided fire con? dition, the closer a reinforced concrete beam is to the fire surface, the faster the heating rate and the higher the temperature will be; (2) the calculation formula of thermal conductivity is modified based on the finite element method,providing a certain level of reference for the selection of parameters for simulation calculation; (3) at the corners between the roof and the middle wall, sidewall it is prone to thermal stress concentration, which will cause greater damage to the structure and should be considered for strengthening in the tunnel fire protection design.
Abstract：
The mechanical properties of reinforced concrete structures under high-temperature environment will be reduced to different degrees, seriously affecting the service life of the structures, however the temperature distribution pattern within the reinforced concrete structures is the basis for the analysis of the fire resistance of the components as well as for repair and reinforcement. In view of this, this paper carries out the indoor fire test to study the temperature propagation pattern within reinforced concrete structures under high-temperature environment based on the actual condition of the reinforced concrete lining of a prefabricated tunnel project in Chengdu. According to the indoor test results, this paper uses the numerical simulation method to optimize the concrete-related thermal parameters and obtains numerical simulation parameters more suitable for actual project condition, and also conducts a thermal coupling analysis on the prefabricated tunnel. The study results show that: (1) under single-sided fire con? dition, the closer a reinforced concrete beam is to the fire surface, the faster the heating rate and the higher the temperature will be; (2) the calculation formula of thermal conductivity is modified based on the finite element method,providing a certain level of reference for the selection of parameters for simulation calculation; (3) at the corners between the roof and the middle wall, sidewall it is prone to thermal stress concentration, which will cause greater damage to the structure and should be considered for strengthening in the tunnel fire protection design.
ZHANG Qiushi1 ZHOU Chuansheng1 SUN Chunping2 LI Huayun1 GUO Zonglin1
.Study on the Pattern of Temperature Propagation of Reinforced Concrete Structure under High-Temperature Environment[J] MODERN TUNNELLING TECHNOLOGY, 2021,V58(4): 185-193
2021, Vol. 58 