Abstract
Structures will be damaged or collapsed when structural members lose their load-carrying capacities at elevated temperatures. Fire resistance design is needed to regulate structures having minimum fire resistance. Although fire resistance design has been enforced in the building codes, there is a lack for performance-based fire resistance design and prediction of fire resistance. In this study, behavior, fire resistance, and effects of the variables of the concrete filled box columns (CFBCs) are investigated to propose evaluation of the fire resistance.
This study explored the research results from literatures and, accordingly, designed eight CFBC specimens. Experiment and finite element analyses were conducted to investigate the behavior of the CFBC specimens, with or without
reinforcement, under fire, and to explore the effects of the variables on the fire behavior. Finally, a recommendation of fire resistance of the CFBCs was proposed on
the basis of the test results of previous research and this study.
The test results showed that a noise of bursting was heard during the test when the CFBC specimens reached maximum axial elongation. It is speculated that the noise was caused by the concrete burst resulting from the difference of temperature and humidity. The magnitude of the applied axial load significant influenced the axial
deformation and behavior of the specimens, and, further, the fire resistance. However, the dimension of the cross section of the specimens and reinforcement had little effects. Finite element analysis could reasonably predict the temperature distribution and trend of the axial deformation of the specimens. Analysis results indicated that the magnitude of the applied load was a major variable affecting the fire resistance. Only
some of the specimens designed in accordance with Eurocode reached the code specified fire resistance. Moreover, the fire resistance formulas used for the concrete
filled tube columns were not suitable to evaluate the fire resistance of the CFBCs.
Therefore, a fire resistance formula was proposed to access the fire resistance of the CFBCs. The fire resistance of the CFBCs mainly related to the ratio of applied axial
load to the load-carrying capacities of the reinforced concrete.
According to these research results, the following suggestions are proposed.
For immediate strategy:
The fire behavior of the concrete filled box columns with reinforcement should be studied. The CFBC specimens with reinforcement had slightly better behavior the specimens without reinforcement. Therefore, the research is needed to further
investigate the effects of amount of the reinforcement, concrete cover, and spacing of the lateral tie on the fire behavior.
For long-term strategy:
Performance-based fire resistance design is needed to be established for domestic building structures. A performance-based fire resistance design is to state the safety goals and to design the structures to fulfill the requirements. Based on many research results conducted by the ABRI, it is necessary to establish the performance-based fire resistance design for the CFBCs.
This study explored the research results from literatures and, accordingly, designed eight CFBC specimens. Experiment and finite element analyses were conducted to investigate the behavior of the CFBC specimens, with or without
reinforcement, under fire, and to explore the effects of the variables on the fire behavior. Finally, a recommendation of fire resistance of the CFBCs was proposed on
the basis of the test results of previous research and this study.
The test results showed that a noise of bursting was heard during the test when the CFBC specimens reached maximum axial elongation. It is speculated that the noise was caused by the concrete burst resulting from the difference of temperature and humidity. The magnitude of the applied axial load significant influenced the axial
deformation and behavior of the specimens, and, further, the fire resistance. However, the dimension of the cross section of the specimens and reinforcement had little effects. Finite element analysis could reasonably predict the temperature distribution and trend of the axial deformation of the specimens. Analysis results indicated that the magnitude of the applied load was a major variable affecting the fire resistance. Only
some of the specimens designed in accordance with Eurocode reached the code specified fire resistance. Moreover, the fire resistance formulas used for the concrete
filled tube columns were not suitable to evaluate the fire resistance of the CFBCs.
Therefore, a fire resistance formula was proposed to access the fire resistance of the CFBCs. The fire resistance of the CFBCs mainly related to the ratio of applied axial
load to the load-carrying capacities of the reinforced concrete.
According to these research results, the following suggestions are proposed.
For immediate strategy:
The fire behavior of the concrete filled box columns with reinforcement should be studied. The CFBC specimens with reinforcement had slightly better behavior the specimens without reinforcement. Therefore, the research is needed to further
investigate the effects of amount of the reinforcement, concrete cover, and spacing of the lateral tie on the fire behavior.
For long-term strategy:
Performance-based fire resistance design is needed to be established for domestic building structures. A performance-based fire resistance design is to state the safety goals and to design the structures to fulfill the requirements. Based on many research results conducted by the ABRI, it is necessary to establish the performance-based fire resistance design for the CFBCs.
| Original language | Chinese (Traditional) |
|---|---|
| Publisher | 內政部建築研究所 |
| Number of pages | 110 |
| ISBN (Print) | 9789860394498 |
| State | Published - Dec 2013 |
Keywords
- fire
- filled composite column
- fire resistance