scholarly journals Analysis of Concrete-Filled Steel Tube Reinforced Concrete Column-Steel Reinforced Concrete Beam Plane Frame Structure Subjected to Fire

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Yanhong Bao ◽  
Bowen Chen ◽  
Lei Xu
Keyword(s):  
Reinforced Concrete ◽  
Fire Resistance ◽  
Load Ratio ◽  
Reinforced Concrete Beam ◽  
Steel Tube ◽  
Frame Structure ◽  
Fire Load ◽  
Steel Reinforced Concrete ◽  
Plane Frames ◽  
Plane Frame

The ABAQUS finite-element analysis platform was used to understand the mechanical behavior of concrete-filled steel tube reinforced concrete (CFSTRC) columns and steel reinforced concrete (SRC) beam plane frames under fire conditions. Thermal parameters and mechanical constitutive model of steel and concrete materials were reasonably selected, the correct boundary conditions were chosen, and a numerical model for the thermal mechanical coupling of CFSTRC columns and SRC beam plane frame structure was established. The finite-element model was verified from related experimental test results. The failure modes, deformation, and internal force distribution of the CFSTRC column and SRC beam plane frames were analyzed under ISO-834 standard fire conditions and with an external load. The influence of beam and column fire-load ratio on the fire resistance of the frame structure was established, and the fire-resistance differences between the plane frame structures and columns were compared. The CFSTRC column-steel reinforced concrete beam plane frame may undergo beam failure or the column and beam may fail simultaneously. The frame structure fire-resistance decreased with an increase of column and beam fire-load ratio. The column and beam fire-load ratio influence the fire resistance of the frames significantly. In this numerical example, the fire resistance of the frames is less than the single columns. It is suggested that the fire resistance of the frame structure should be considered when a fire-resistant structural engineering design is carried out.

Experimental study on the fire resistance of concrete filled steel tube reinforced concrete (CFSTRC) column-RC beam frames

2021 ◽  
pp. 136943322110015
Author(s):  
Lei Xu ◽  
Yan-Hong Bao
Keyword(s):  
Reinforced Concrete ◽  
Cross Sections ◽  
Fire Resistance ◽  
Failure Modes ◽  
Load Ratio ◽  
Steel Tube ◽  
Stiffness Ratio ◽  
Fire Load ◽  
Concrete Core ◽  
Concrete Filled Steel Tube

To reveal the temperature characteristics and mechanical properties of frame structures with concrete filled steel tube reinforced concrete (CFSTRC) columns under fire, the fire resistance of four planar frames consisting of CFSTRC columns and reinforced concrete (RC) beams subjected to ISO-834 standard fire was tested in this study. The test parameters included the column fire load ratio, beam fire load ratio, and beam-to-column linear stiffness ratio. In the test, the temperatures of the column, beam, and slab cross-sections in the joint and nonjoint zones were measured, and the fire resistance, beam and column deformation curves, and failure modes of the frame were investigated. The experimental results showed that the concrete volume was the main factor affecting the temperature distribution on each typical cross-section of the frame: the temperatures at the measuring points of the beam and column in the joint zone were significantly lower than the temperatures at the corresponding points in the nonjoint zone, and the concrete outside the steel tube significantly slowed the propagation of temperature to the steel tube and its concrete core. Hence, there was only a small loss of the bearing capacity of steel tube and the core concrete inside the steel tube. The column fire load ratio, beam fire load ratio, and beam-to-column linear stiffness ratio have obvious influences on the fire resistance: the larger the column fire load ratio or beam fire load ratio, the smaller the fire resistance; and the larger the beam-to-column linear stiffness ratio, the larger the fire resistance.

Calculation of Ultimate Bearing Capacity of Prestressed Steel Reinforced Concrete Structure under Fire

2011 ◽  
Vol 250-253 ◽  
pp. 2857-2860 ◽  
Author(s):  
Yu Zhuo Wang ◽  
Chuang Guo Fu
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Fire Resistance ◽  
Concrete Structure ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Ultimate Bearing Capacity ◽  
Reinforced Concrete Structure ◽  
Steel Reinforced Concrete ◽  
Resistance Performance

Prestressed steel reinforced concrete structure, compared with other concrete structure has its unique advantages. So it is mainly used in large span and conversion layers. With the popularization of this structure,more attention should be payed on fire resistance performance. On the basis of reasonable assume,two steps model is used as concrete high strength calculation model. Simplified intensity decreased curve is used as rebar,steel and prestressed. Two ultimate bearing capacity formulas of prestressed steel reinforced concrete beam are established. One is for the beam whose tensile area is under fire, the other is for the beam whose compression area is under fire. Prestressed steel reinforced concrete structure has both prestressed concrete structure’s advantages and steel reinforced concrete structure ’s advantage. Steel reinforced concrete is used to improve the bearing capacity of the structure. Prestressed steel is used to improve the ultimate state of structure’s performance during normal use. Thereby structure’s performance is better to play. There are many similarities between prestressed steel reinforced concrete structure and steel reinforced concrete structure about fire resistance performance. Because of prestressed steel reinforced concrete structure’s own characteristics, there are still many problems about fire resistance. This paper mainly presented bending terminal bearing capacity of prestressed steel reinforced concrete beam under fire. Established simplified formulae for calculation, it is meet the engineering accuracy requirement.

scholarly journals Analysis of Fire Resistance of Square-Cased Square Steel Tube Reinforced Concrete (ST-RC) Columns

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5541
Author(s):  
Gaoxiong Wang ◽  
Yanhong Bao ◽  
Li Yang ◽  
Yang Yu
Keyword(s):  
Reinforced Concrete ◽  
Fire Resistance ◽  
Slenderness Ratio ◽  
Concrete Strength ◽  
Load Ratio ◽  
Internal Force ◽  
Steel Tube ◽  
Fe Model ◽  
Cross Sectional ◽  
Rc Columns

Based on the finite element (FE) analysis software Abaqus, an FE model of square-cased square steel tube reinforced concrete (ST-RC) columns under the hybridized action of high-temperature and load is established. The accuracy of the FE model is verified using experimental data from existing studies. This model is used to analyze the temperature change, internal force distribution, and failure characteristics of the square-cased square ST-RC columns under the action of fire, as well as the factors affecting the fire resistance limit of the column. The results of FE analysis show that under the action of fire, the maximum internal temperature of the square-cased square ST-RC columns occurs in the corner of the section. Moreover, the stress and strain reach their maximum values at the concrete corner outside the tube. During the heating process, an internal force redistribution occurs in the square-cased square ST-RC column. At the same time, the proportion of the axial force and the bending moment of the reinforced concrete outside the pipe decreases gradually, while the proportion of the internal force of the core concrete-filled steel tube (CFST) increases gradually. In essence, it is a process of load transfer from the high-temperature to the low-temperature zone. In addition, the section size, load ratio, slenderness ratio, cross-sectional core area ratio, steel content, and external concrete strength are the main parameters affecting the fire resistance limit of the square-cased square ST-RC columns. Among them, the cross-sectional core area ratio, section size, steel ratio, and external concrete strength are positively correlated with the fire resistance limit of the composite column. On the contrary, with the increase in the load ratio and the slenderness ratio, the fire resistance limit of the square-cased square ST-RC columns decreases. On this basis, a simplified formula to calculate the fire resistance limit of square-cased square ST-RC columns is proposed. The research results can be used as a theoretical reference for the fire protection design of this kind of structure in practical engineering.

Performance of Frame Structure Composed of Steel Reinforced Concrete Beam and Angle-Steel Concrete Column under Horizontal Loading

2012 ◽  
Vol 204-208 ◽  
pp. 1094-1101 ◽  
Author(s):  
Kun Wang ◽  
Hui Hui Luo ◽  
Wen Zhong Zheng
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Failure Modes ◽  
Reinforced Concrete Beam ◽  
Frame Structure ◽  
Concrete Column ◽  
Steel Reinforced Concrete ◽  
Composite Frame ◽  
Horizontal Loading ◽  
Angle Steel

This paper developed a finite element modelling (FEM) to simulate two frame specimens composed of steel reinforced concrete beam and angle-steel concrete column under horizontal loading. In the FEM, a series of simulation technologies such as defining material models, selecting element types, applying load, and parameters determination were described. Through the FEM, the skeleton curves, failure modes, and strain distribution are acquired, and the calculated results are basically agree well with the tests. Furthermore, the mechanism of the composite frame structure under horizontal loading is analyzed.

Modelling and Analysis of the Bottom Frames of Multi-Story Masonry Buildings Exposed to Fire

2011 ◽  
Vol 255-260 ◽  
pp. 704-708
Author(s):  
Kai Yan ◽  
Wen Zhong Zheng ◽  
Ying Wang
Keyword(s):  
Reinforced Concrete ◽  
Fire Resistance ◽  
Plastic Material ◽  
Yield Criterion ◽  
Load Ratio ◽  
Material Model ◽  
Masonry Buildings ◽  
Concrete Frames ◽  
Fire Load ◽  
Load Effect

The multi-story masonry buildings with reinforced concrete frames on ground floors collapse more easily than pure frames when bottom frames exposed to fire, for reasons that fire load of its ground floors is relatively large, and the ratio of dead load to the total loads is also large, deformations of joists caused by fire produce adverse effect on arch mechanism of masonry. For the purpose of loading temperature on steel bars and concrete for fire resistance analysis of reinforced concrete structures in ABAQUS, separated loading method is proposed firstly in this article. The Hill yield criterion for compression and the Rankine yield criterion for tension are adopted to establish anisotropic elasto-plastic material model for masonry. The process simulation from temperature rises to buildings collapse is realized. A parametric study is conducted to investigate the effects on fire resistance of the bottom frames when the bottom floors exposed to fire due to the change in effective load ratio, section size and reinforcement ratio. The study shows that the failure mode of the bottom frames exposed to fire is mainly due to columns collapse. Bottom fames designed with seismic class I and II have relatively more safety storage than non-seismic designed bottom frames to resist the fire load effect, and they can satisfy time limits of fire resistance.

Fire Performance of CFST, SRC and RC Frames

2011 ◽  
Vol 99-100 ◽  
pp. 300-303
Author(s):  
Guang Yong Wang ◽  
Xing Qiang Wang ◽  
Guang Wei Liu ◽  
Xiao Yang Liu ◽  
Da Fang Ma
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Failure Mechanism ◽  
Fire Resistance ◽  
Room Temperature ◽  
Steel Tube ◽  
Frame Structures ◽  
Fire Performance ◽  
Steel Reinforced Concrete ◽  
Rc Frames

Failure mechanism and fire resistance comparison of concrete-filled steel tube (CFST) frames, reinforced concrete (RC) frames and steel reinforced concrete (SRC) fames are proposed in this paper when their bearing capacity and rigidity at room temperature are similar. The result shows that the failure mode and failure mechanism of the 3 frame structures are much different, and the SRC frames have the maximum fire resistance.

Damage Sensitivity Analysis for Main Design Parameters of Steel Reinforced Concrete Beam

2011 ◽  
Vol 374-377 ◽  
pp. 2562-2565
Author(s):  
Shan Suo Zheng ◽  
Yi Hu ◽  
Qing Lin Tao ◽  
Zhi Qiang Li
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Flexural Rigidity ◽  
Reinforced Concrete Beam ◽  
Frame Structure ◽  
Design Parameters ◽  
Load Effect ◽  
Main Design ◽  
Steel Reinforced Concrete ◽  
Steel Ratio

Considering of the condition that the steel reinforced concrete beam is mainly used to bear the vertical load and preserve the robustness of integrated structure, this paper takes the flexural rigidity of beam subjected to short-term load effect as the damage characterization of SRC beam. According to the related theoretical analysis and experimental research, the damage sensitivity of various design parameters which contain the sectional height, the strength of concrete and steel ratio are analyzed, and the influence laws of main design parameters impacted on damage evolution of SRC beam are revealed. The research shows that sectional height is proved to be the most sensitive factor in the damage of SRC beam and the steel ratio takes the second place, and then the strength of concrete is the most insensitive to the damage of SRC beam. The research achievements will provide theory and date support for establishing the storey damage model of SRC frame structure under seismic excitation.

Flexural Capacity Study on Square Tube Filled with Steel Reinforced Concrete Members

2010 ◽  
Vol 163-167 ◽  
pp. 1574-1577 ◽  
Author(s):  
Tong Feng Zhao ◽  
Hong Nan Li ◽  
Jia Huan Yu
Keyword(s):  
Reinforced Concrete ◽  
Steel Tube ◽  
Flexural Capacity ◽  
Steel Reinforced Concrete ◽  
Deformation Curves ◽  
Concrete Members ◽  
Bending Load ◽  
Square Steel Tube ◽  
Abaqus Software

Moment-deformation curves of square steel tube filled with steel reinforced concrete subjected to bending load were simulated by the ABAQUS software. Calculated and experimental curves agreed well with each other. Through studying further the calculated member, the behavior of materials subjected to moment is given. Finally, flexural capacity formula of square steel tube filled with cross steel reinforced concrete is proposed.

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