FIRE RESISTANCE OF CIRCULAR STEEL TUBE COLUMNS INFILLED WITH REINFORCED CONCRETE

Fire and post-fire behaviours of reinforced concrete columns confined by circular steel tubes, also known as circular steel tube confined reinforced concrete (STCRC) columns, are investigated in this paper. 5 full-scale specimens exposed to fire and 47 specimens after fire exposure were tested. Temperatures across the sections, displacement versus time curves, fire resistance, load versus displacement responses and load-bearing capacities were measured and discussed. A finite element (FE) model was developed using the program ABAQUS, and validated against the test results from the present study. Simplified design methods were proposed for predicting the fire resistance and residual load-bearing capacity of the STCRC columns under and after fire exposure, respectively.

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Shear Bearing Capacity of Framework Joints of Steel-Reinforced Concrete-Filled Circular Steel Tube

Advances in Materials Science and Engineering ◽

10.1155/2020/7324865 ◽

2020 ◽

Vol 2020 ◽

pp. 1-15

Author(s):

Yongjun Lin ◽

Kaiqi Liu ◽

Tianxu Xiao ◽

Chang Zhou

Keyword(s):

Reinforced Concrete ◽

Bearing Capacity ◽

Plastic Material ◽

Element Model ◽

Steel Tube ◽

Shear Capacity ◽

Steel Reinforced Concrete ◽

Shear Mechanism ◽

Circular Steel Tube ◽

Shear Bearing Capacity

In this paper, in order to investigate the shear mechanism and shear capacity of framework joints of steel-reinforced concrete-filled circular steel tube (SRCFCST), a numerical finite element model reflecting the mechanical behavior of framework joints of SRCFCST column-reinforced concrete beam is established through simulating concrete by the damage plastic constitutive model and simulating steel by the ideal elastic-plastic material, and its effectiveness is verified by experimental data. On account of uniform distribution of circular steel reinforced around the section and without definite flange and web, the shear mechanism of the framework joints of SRCFCST is analyzed on the basis of equivalent circular steel tube (CST) to the rectangular steel tube. The method for calculating the superposed shear bearing capacities of the joint core area is proposed, which is composed of four parts, i.e., concrete inside tube, concrete outside tube, hooping and steel-reinforced web; and the corresponding formulas for calculating shear bearing capacity are established. The comparative analysis of joints’ shear bearing capacity indicates that the results of numerical simulation and shear bearing capacity formulas coincide well with the experimental values, which can provide reference for the nonlinear analysis and engineering design of similar joints.

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Ultimate Bearing Capacity Analysis of Axially Compressive Circular Steel Tube Columns Filled with Bar-Reinforced Concrete

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.94-96.1205 ◽

2011 ◽

Vol 94-96 ◽

pp. 1205-1210

Author(s):

Zhao Liu ◽

Jun Hai Zhao

Keyword(s):

Reinforced Concrete ◽

Bearing Capacity ◽

Steel Tube ◽

Ultimate Bearing Capacity ◽

Strength Theory ◽

Principal Stresses ◽

Unified Strength Theory ◽

Short Columns ◽

Circular Steel Tube ◽

Circular Bar

The mechanical behavior and ultimate bearing capacity of the circular bar-reinforced concrete filled steel tube (BRCFST) short columns under axial compression are analyzed in this paper based on the unified strength theory. Considering the restriction effect of steel tube and hoop bar on concrete, the calculation formula of bearing capacity of the column is deduced. Parametric studies are carried out to evaluate the effects of intermediate principal stresses, diameter-thickness ratio of steel tube and the stirrup ratio on the bearing capacity of the column. A good agreement is reached by comparing the results calculated by the formula with the test results. It is concluded that the unified strength theory is applicable in the theoretical analyses of the BRCFST columns.

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Finite Element Analysis on Circular Steel Tube Composite Column Filled with Steel Reinforced Concrete

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.166-169.318 ◽

2012 ◽

Vol 166-169 ◽

pp. 318-321

Author(s):

Ya Feng Xu ◽

Xu Yang ◽

Xin Wang ◽

Shou Yan Bai

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Reinforced Concrete ◽

Axial Compression ◽

Steel Tube ◽

Element Analysis ◽

Steel Reinforced Concrete ◽

Axial Compression Ratio ◽

Circular Steel Tube ◽

Deformation Ability

The article analysis the seismic behaviors of circular steel tube composite column filled with steel reinforced concrete by the large finite element analysis software ABAQUS, adopted the load-displacement method and aimed at studying the mechanical properties of circular steel tube composite columns filled with steel reinforced concrete under horizontal low-cyclic loading, considering the degree of ductility, capacity of energy dissipation by the steel ratio and axial compression ratio. Under different axial compression ratios and steel ratios, the hysteresis curves and skeleton curves are carried out. Along with the increase of steel ratio, the deformation ability and ultimate bearing capacity are raised, but with the increase of axial compression ratio, the deformation ability becomes worse.

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

Advances in Civil Engineering ◽

10.1155/2021/6620030 ◽

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.

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Fire resistance of thin-walled steel tube confined reinforced concrete middle-length columns: Test and numerical simulation

Structures ◽

10.1016/j.istruc.2021.07.078 ◽

2021 ◽

Vol 34 ◽

pp. 339-355

Author(s):

Xuhong Zhou ◽

Jingjie Yang ◽

Jiepeng Liu ◽

Shang Wang ◽

Weiyong Wang

Keyword(s):

Numerical Simulation ◽

Reinforced Concrete ◽

Fire Resistance ◽

Steel Tube ◽

Thin Walled

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Under Axial Load Finite Element Analysis of Characteristics of Circular Steel Tube Compile Short Column Filled with Steel Reinforced Concrete

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.588-589.212 ◽

2012 ◽

Vol 588-589 ◽

pp. 212-216

Author(s):

Rui Jing ◽

Yong Sheng Zhang

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Reinforced Concrete ◽

Bearing Capacity ◽

Steel Tube ◽

Element Analysis ◽

Steel Reinforced Concrete ◽

Short Column ◽

Circular Steel Tube ◽

Core Concrete

With the help of large general finite element analysis software ANSYS, under different parameters, this paper will have a finite element analysis of bearing capacity on circular steel tube compile short column filled with steel reinforced concrete(STCSRC).In the paper,it uses separate models to calculate and analyze.Considering the nonlinear constitutive relation of steel and concrete and determining the type of unit,it is shown that stress distribution and load-displacement curve of specimen under the effect of different parameters.According to the curve and data,analysis results of bearing capacity of specimen have been shown that bearing capacity of STCSRC will increase with concrete strength increasing and it also will increase with steel rate increasing under axial load.Because of core concrete working together with steel tube and angle steel,it can significantly improve the bearing capacity of composite columns, slow down and inhibit shearing inclined cracks occur in the core concrete and develop,and improve the ductility of columns.

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Experimental Research of FRP Composite Tube Confined Steel-reinforced Concrete Stub Columns Under Axial Compression

E3S Web of Conferences ◽

10.1051/e3sconf/20183803035 ◽

2018 ◽

Vol 38 ◽

pp. 03035

Author(s):

Ji Zhong Wang ◽

Lu Cheng ◽

Xin Pei Wang

Keyword(s):

Reinforced Concrete ◽

Axial Compression ◽

Load Capacity ◽

Compressive Load ◽

Steel Tube ◽

Composite Tube ◽

Steel Reinforced Concrete ◽

Frp Composite ◽

Circular Steel Tube ◽

Stub Columns

A new column of FRP composite tube confined steel-reinforced concrete (FTCSRC) column was proposed. This paper elaborates on laboratorial and analytical studies on the behavior of FCTSRC columns subjected to axial compressive load. Eight circular FTCSRC stub columns and one circular steel tube confined concrete (STCC) stub column were tested to investigate the failure mode and axial compression performance of circular FTCRSC columns. Parametric analysis was implemented to inquire the influence of confinement material (CFRP-steel tube or CFRP-GFRP tube), internal steel and CFRP layers on the ultimate load capacity. CFRP-steel composite tube was composed of steel tube and CFRP layer which was wrapped outside the steel tube, while CFRP-GFRP composite tube was composite of GFRP tube and CFRP layer. The test results indicate that the confinement effect of CFRP-steel tube is greatly superior to CFRP-GFRP tube. The ductility performance of steel tube confined high-strength concrete column can be improved obviously by encasing steel in the core concrete. Furthermore, with the increase in the layers of FRP wraps, the axial load capacity increases greatly.

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

Materials ◽

10.3390/ma14195541 ◽

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.

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