The Square Steel Tube Columns Filled with Steel-Reinforced Concrete Bias Supporting Capacity Unified Solution

2012 ◽  
Vol 193-194 ◽  
pp. 1418-1423
Author(s):  
Zhi Jie Liu ◽  
Jun Hai Zhao ◽  
Xu Guang Yu ◽  
Gai Qin Su ◽  
Xin Zhao

The eccentric ultimate load calculation formula of square steel tube columns filled with steel-reinforced concrete was derived based on the Unified Strength Theory in this paper. The influence of intermediate principal stress and the restriction effect and the decrease of longitudinal stress were considered in the formula. Based on the axial compression load and the effect of consider the eccentricity ratio and slenderness ratio on the hearing capacity was considered, by introducing the reduction factor of concrete strength and the equivalent restriction reduction factor, the confinement of square steel tube towards concrete was equivalent to the confinement of circular steel tube towards it, based on unified strength theory solutions of thick tube, the calculation formula of eccentric compression bearing capacity of square steel tube columns filled with steel-reinforced concrete was deduced and analysed the influence complication. The results indicate unified strength theory has the good applicability and the solution has an important practical value for engineering application.

2011 ◽  
Vol 94-96 ◽  
pp. 1205-1210
Author(s):  
Zhao Liu ◽  
Jun Hai Zhao

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.


2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Tongfeng Zhao

In the present study, an experimental research was conducted on square steel tube confined steel reinforced concrete column under eccentric load. The major parameters of the specimens included slenderness ratio, eccentricity ratio, and structural steel reinforced ratio. According to the tested results, the eccentricity ratio, from 0 to 0.55, significantly affects the structural bearing capacity. The slenderness ratio, from 3 to 8, and steel reinforced ratio, from 0.3 to 0.41, slightly affect the capacity. Furthermore, a numerical analysis program was developed, and the calculated results are well consistent with the experimental results. Also, the theoretical formula for eccentrically loaded columns was proposed based on numerical results.


2015 ◽  
Vol 723 ◽  
pp. 422-426
Author(s):  
Rong Zhou ◽  
Jun Hai Zhao ◽  
Xue Ying Wei

The ultimate load calculation formula for the solid multi barrel tube-confined concrete columns (CHS inner and SHS outer) was derived based on the Unified Strength Theory (UST) in this paper. The influence of intermediate principal stress and the double restriction effect and the decrease of longitudinal stress were considered in the formula. Based on the axial compression load and consider the eccentricity ratio and slenderness ratio, by introducing the reduction factor of concrete strength and the equivalent restriction reduction factor, based on unified strength theory solutions of thick tube, combined with concrete filled skin tube unified theory, deduce the calculation formula of eccentric compression bearing capacity of concrete filled steel tubular columns and analysis the influence complication.


2010 ◽  
Vol 163-167 ◽  
pp. 1574-1577 ◽  
Author(s):  
Tong Feng Zhao ◽  
Hong Nan Li ◽  
Jia Huan Yu

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.


2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Yongjun Lin ◽  
Kaiqi Liu ◽  
Tianxu Xiao ◽  
Chang Zhou

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.


2013 ◽  
Vol 690-693 ◽  
pp. 742-746
Author(s):  
Peng Wu ◽  
Jian Feng Xu ◽  
Jun Hai Zhao ◽  
Qian Zhu ◽  
Su Wang

Based on unified strength theory, the mechanical behavior of core-concrete of concrete-filled square steel tubular stub columns was analyzed. Through controlling the constraint effect between square steel tube and core-concrete by width-thickness ratio, the ultimate bearing capacity formula for concrete-filled square steel tubular stub columns under axial compression was proposed, and the influencing factors of which was also discussed. The rationality of proposed formula was proved from the comparison of the analytical results obtained in this paper and experimental data.


2012 ◽  
Vol 166-169 ◽  
pp. 318-321
Author(s):  
Ya Feng Xu ◽  
Xu Yang ◽  
Xin Wang ◽  
Shou Yan Bai

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.


2012 ◽  
Vol 490-495 ◽  
pp. 3177-3181
Author(s):  
Xiao Liu ◽  
Lei Zhao

Steel tube filled with steel-reinforced concrete (STSRC) is a new kind of heavy load column, which made by inserting steel skeletons into the steel tube, then injecting the concrete to the tube. In order to study the combined column’s stability subject to axial compression, we use energy method and numerical methods analysis derives the formula of stability coefficient in which slenderness ratio as the main parameters. Using the 1/1000 column length as the initial deflection of the STSRC columns by FORTUNE calculation program, stability coefficient is produced through comparison and analysis between calculated results from quantile regression and that from ordinary least square regression respectively. According to the computer results and energy method, the formula for calculating the axial stability bearing capacity of STSRC was established. A good agreement between the calculation results and testing results illustrates, which is feasible to using the calculating formula to calculate the bearing capacity of STSRC


2010 ◽  
Vol 163-167 ◽  
pp. 4542-4545 ◽  
Author(s):  
Xin Zhong Li ◽  
Xue Ying Wei ◽  
Jun Hai Zhao

This paper presents the theoretical and experimental results of concrete-filled steel tube columns subjected to axially compression. A total of 6 specimens with outer square sections reinforced by inner cicular steel tube were constructed for experimental investigation. The ultimate strengths of the columns from tests were obtained. The theoretical strengths of the columns were also investigated based on unified strength theory, and compared with the test results. Good agreement can be observed from the comparison.


2012 ◽  
Vol 588-589 ◽  
pp. 212-216
Author(s):  
Rui Jing ◽  
Yong Sheng Zhang

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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