scholarly journals Bearing Capacity of Recycled Self-Compacting Concrete-Filled Circular Steel Tubular Long Columns Subjected to Axial Load

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Feng Yu ◽  
Jie Song ◽  
Shuangshuang Bu ◽  
Jingfeng Wang ◽  
Haiying Wan ◽  
...  

To investigate the ultimate bearing capacity and deformation of the recycled self-compacting concrete-filled circular steel tubular (RSCCFCST) long columns subjected to axial load, nine specimens with different recycled self-compacting concrete (RSCC) strength grades and slenderness ratios are tested. The experimental results indicate that the lateral deflection dominates the buckling failure of the specimens. The ultimate bearing capacity of the specimens is enhanced gradually as the RSCC strength grade increases but decreases as the slenderness ratio rises. The load-strain curves are linear and basically coincide at the elastic stage. The decrease in the slenderness ratio or increase in the RSCC strength grade contributes to the improvement of the stiffness and ultimate circumferential and axial strains of the columns gradually. Based on the combined tangent modulus theory and bearing capacity of the RSCCFCST short columns, two estimation models are presented to predict the ultimate bearing capacity of the RSCCFCST long columns. Additionally, comparisons between the calculation results of the ultimate strength demonstrate that the prediction models established in this study are more accurate than the other specifications mentioned.

2016 ◽  
Vol 847 ◽  
pp. 38-45
Author(s):  
Xian Yan Zhou ◽  
Dan Zeng ◽  
Zhi Feng Wang

At present, the relevant researches of Glulam columns in China are mainly restricted to short columns. In order to study the mechanical properties of long columns under axial loading, an experimental study on five different slenderness ratios of Larch Glulam columns was carried out. With slenderness ratio changing, the variations of experimental data such as axial strain, lateral deflection at mid-height, ultimate bearing capacity, and peak strain were comparatively analyzed. The failure pattern and failure mechanism of long columns were discussed. The results indicate that the ultimate bearing capacity of Larch Glulam columns gradually decreases as the slenderness radio increases and the failure mode is gradually converted from strength failure to instability failure. The ultimate load reduction factor is obtained by regression analysis based on the experiment results of Larch Glulam short columns. The basis for design and application of Larch Glulam columns are provided.


2011 ◽  
Vol 243-249 ◽  
pp. 268-273
Author(s):  
Qing Ma ◽  
Jin Song Lei ◽  
Wen Zhi Yin

Double-limb lipped channel section steel member is formed by connecting two single limb members with bolts in order to improve the buckling performance. In order to research the buckling form and ultimate bearing capacity of members with different slenderness ratios under axial load, nonlinear analysis of buckling performance is done to this kind of section using the finite element analysis software ANSYS. The influence on bearing capacity caused by height-breadth ratio of section, height-thickness ratio of web and breadth-thickness ratio of flange is analyzed. The results show that: (1) for larger slenderness ratio, complete buckling occurs to the column mainly and the slenderness ratio has larger influence on buckling bearing capacity, while for smaller slenderness ratio, local distortional buckling occurs more; (2) in a certain range, the increase of height-breadth ratio could raise the ultimate bearing capacity of member, but excessive height-breadth ratio would make the ultimate bearing capacity decrease, (3) the increase of both height-thickness ratio and breadth-thickness ratio would decrease the ultimate bearing capacity.


2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Feng Yu ◽  
Pengcheng Xu ◽  
Yuan Fang ◽  
Yang Zhang ◽  
Junjie Jiang

In this study, twenty-one recycled self-compacting concrete-filled circular steel tubular (RSCFCST) columns are designed and tested under eccentric compression. The studied parameters including the replacement ratio of the recycled coarse aggregate (RCA), strength grade of concrete, eccentricity, and length-diameter ratio L/D of specimens are considered. The load-stiffness curves of the specimens are obtained by observing the whole process of loading, and the effects of various parameters on the stiffness of the specimens are analyzed. Test results demonstrate that the RSCFCST short columns L/D≤4 under eccentric compression exhibit drum-like bending failures, while the RSCFCST long columns L/D>4 under eccentric compression experience the global flexural buckling failure modes. With the replacement ratio of RCA, the length-diameter ratio or eccentricity increases, and the bearing capacity of specimens under eccentric compression decreases. However, the increase in the strength grade of concrete increases the bearing capacity. The stiffness of the RSCFCST columns under eccentric compression gradually increases as the strength grade of concrete increases, while the eccentricity had an adverse effect on stiffness of specimen. With the increase of load, the increase of the length-diameter ratio would accelerate the stiffness degradation of specimen. The effect of the replacement ratio of RCA on stiffness of specimen in the elastic stage is not obvious. A validated FE model is employed to conduct parametric studies to widen the available test results. Additionally, an analytical model for predicting the effective stiffness of the RSCFCST columns under eccentric compression is proposed based on the moment magnifier method, and verification of this method is performed using the test data and FE analysis.


Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 329
Author(s):  
Jun Wang ◽  
Xinran Wang ◽  
Yuxin Duan ◽  
Yu Su ◽  
Xinyu Yi

At present, the existing standards (AISC360-16, EN1994-1-1:2004, and JGJ138-2016) lack relevant provisions for steel-reinforced concrete (SRC) composite columns with high-strength steel. To investigate the axial compressive mechanical performance of short high-strength steel-reinforced concrete (HSSRC) columns, the axial load test was conducted on 12 short composite columns with high-strength steel and ordinary steel. The influences of steel strength, steel ratio, and the section form of steel on the failure modes, bearing capacity, and ductility of the specimens were studied. Afterward, the experimental data were compared with the existing calculation results. The results show: compared with the specimens with Q235 steel, the bearing capacity of the specimens with Q460 steel increases by 7.8–15.3%, the bearing capacity of the specimens with Q690 steel increases by 13.2–24.1%, but the ductility coefficient increases by 15.2–202.4%; with the increase of steel ratio, the bearing capacity and ductility of specimens are significantly improved. A change of the steel cross-section could influence the ductility of SRC columns more than their bearing capacity. Moreover, the calculation results show that present standards could not predict the bearing capacity of HSSRC columns. Therefore, a modified method for determining the effective strength of steel equipped in HSSRC columns was proposed. The results of the ABAQUS simulation also showed that the addition of steel fibers could significantly improve the bearing capacity of Q690 HSSRC columns. The research results provide a reference for engineering practices.


2014 ◽  
Vol 915-916 ◽  
pp. 146-149
Author(s):  
Yong Sheng Wang ◽  
Li Hua Wu

The finite element model of the space KX-Joint was established using ANSYS software, and the failure mode and ultimate bearing capacity of KX-joint were researched. Calculation results show that the surface of chord wall on the roots of compression web members was into the plastic in K plane, and the holding pole without the plastic area and the local buckling failure happened in the surface of chord wall on the roots of Compression Web Members in X plane; The bearing capacity of the joint increased with the Chord diameter, which was appears in the form of power function.


2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Xianglong Liu ◽  
Jicheng Zhang ◽  
Hailin Lu ◽  
Ning Guan ◽  
Jiahao Xiao ◽  
...  

The mechanical properties of T-shaped concrete-filled steel tubular (TCFST) short columns under axial compression after elevated temperature are investigated in this paper. A total of 30 TCFST short columns with different temperature (T), steel ratio (α), and duration of heating (t) were tested. The TCFST column was directly fabricated by welding two rectangular steel tubes together. The study mainly investigated the failure modes, the ultimate bearing capacity, the load-displacement, and the load-strain performance of the TCFST short columns. Experimental results indicate that the rectangular steel tubes of the TCFST column have deformation consistency, and the failure mode consists of local crack, drum damage, and shear failure. Additionally, the influence of high temperature on the residual bearing capacity of the TCFST is significant, e.g., a higher temperature can downgrade the ultimate bearing capacity. Finally, a finite element model (FEM) is developed to simulate the performance of the TCFST short columns under elevated temperature, and the results agree with experimental values well. Overall, this investigation can provide some guidance for future studies on damage assessment and reinforcement of the TCFST columns.


2020 ◽  
Vol 198 ◽  
pp. 02017
Author(s):  
Zhongju Feng ◽  
Shaofen Bai ◽  
Wu Min ◽  
Jingbin He ◽  
Zhouyi Huang ◽  
...  

In order to study the influence of steep slope-karst coupling on the vertical bearing characteristics of pile foundation, the orthogonal simulation tests of pile foundation under 4 different roof thickness and 5 different slope are carried out by using Marc finite element software, and the correction coefficient of vertical partial bearing capacity of pile foundation according to roof thickness and slope is put forward. The test results show that when the thickness of the roof is more than 3 times the pile diameter, the ultimate bearing capacity of the pile foundation tends to be stable, and the value is about 19% when the slope is 45°; the ultimate bearing capacity of the pile foundation decreases gradually with the increase of the slope, and the reduction reaches 29.83% when the slope is greater than 45°. According to the calculation results, the variation law of vertical partial bearing capacity of pile foundation is analyzed, and the calculation formula of standard value of vertical ultimate bearing capacity of pile foundation in steep slope karst area considering both roof thickness and slope is put forward, and the correction coefficients αi and β are put forward.


2012 ◽  
Vol 594-597 ◽  
pp. 987-992
Author(s):  
Chun Lei Fan ◽  
Ji Ping Hao ◽  
Wei Feng Tian

Experiment on bearing capacity of 24 Q460 high strength angle steel for compression members attached by one leg shows: the ultimate bearing capacity of the experiment value are higher than the calculated of the “Design of Latticed Steel Transmission Structures” (ASCE10-1997), on the same section in different slenderness ratio of components, the larger slenderness ratio, the higher the ratio; while on the same slenderness ratio in different sections, the greater width-thickness radio, the greater the ratio. Based on this problem, analyzing the current standard, a set of formulas based on high-strength angle struts connected by single Limb was brought, which can used for the design of the Q460 high-strength angle.


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.


2011 ◽  
Vol 94-96 ◽  
pp. 220-224 ◽  
Author(s):  
Xi Guang Cui ◽  
Hai Dong Xu

Considering the strain rate then puts forward the modified uniaxial dynamic constitutive model related to strain rate in concrete-filled square steel tube and the modified calculation results match well with the experimental results. Based on the above conclusion, uniaxial compression performance finite element analysis with different strain rate among 10-5/s–10-3/s is completed, the results showed that strain rate can obviously change the dynamic performance of the concrete-filled square steel tube. Through the analysis of the influencing factors of the core concrete compressive strength, it is showed that with the increasing of the strain rate and the improving of concrete strength, the ultimate bearing capacity of concrete-filled square steel tube is higher and the ductility is reduced. With the increasing of stirrup ratio, ultimate bearing capacity is greater and the ductility is enhanced. With the sectional dimensions increasing, the ultimate bearing capacity is greater and the ductility is enhanced.


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