Efficiency on uni-axial compressive strength improvement by using externally confined concrete-filled steel tube columns

2013 ◽  
Vol 20 (2) ◽  
pp. 96-108
Author(s):  
J. C.M. Ho ◽  
L. Luo
2011 ◽  
Vol 368-373 ◽  
pp. 410-414 ◽  
Author(s):  
Hong Zhen Kang ◽  
Lei Yao ◽  
Xi Min Song ◽  
Ying Hua Ye

To study axial compressive strength of high strength concrete-filled steel tube composite columns, tests of 18 specimens were carried out. Parameters of the specimens were the confinement index of concrete-filled steel tube, the cubic strength and the stirrup characteristic value of concrete outer of steel tube. Test results show that the concrete-filled steel tube and the reinforced concrete deformed simultaneously in the axial direction before and at the peak value of axial compressive force; after failure of the reinforced concrete, the concrete-filled steel tube can still bear the axial load and deformation; the main influential factors of axial compressive capacity are confinement index, the cubic strength and the stirrup characteristic value of concrete outer of steel tube. The accuracy of the formula of axial compressive strength of composite columns provided by CECS 188:2005 is proved by the test results of this paper.


2018 ◽  
Vol 4 (11) ◽  
pp. 2529
Author(s):  
Tanyada Pannachet ◽  
Maetee Boonpichetvong

This paper investigated effect of concrete strength on axial strength improvement of the metal sheet confined concrete cylinders under axial compression. Totally, 27 concrete specimens were tested based on three different concrete strengths of approximately 13, 32 and 39 MPa. Epoxy was used as a bonding material along interface between concrete and metal sheet. Based on three different concrete strengths, different level of confinement was established by taking one layer and three layers of metal sheet confinement. The experimental results revealed that axial compressive strength of concrete cylinders could be improved by mean of metal sheet wrapping. It was shown that effectiveness of axial strength improvement of metal sheet confined concrete cylinders depended on original unconfined compressive strength of the core concrete. With lower concrete strength, it was found that use of metal sheet confinement could increase the original strength of the columns more effectively than the case of higher concrete strength. Based on existing results, it was observed that strength improvement prediction given by Richart et al. (1928) could be adopted conservatively with exception of very low concrete strength.


Structures ◽  
2021 ◽  
Vol 31 ◽  
pp. 558-575
Author(s):  
Yu-Hang Wang ◽  
Yu-Yan Wang ◽  
Xu-Hong Zhou ◽  
Ran Deng ◽  
Yong-Sen Lan ◽  
...  

2010 ◽  
Vol 163-167 ◽  
pp. 3826-3829
Author(s):  
Feng Yu ◽  
Ping Wu

FRP-confined concrete filled steel tube may fully use the character of FRP-confined concrete and concrete filled steel tube. Based on the analysis of existing experimental data, the formula of ultimate bearing capacity of FRP-confined concrete filled steel tube is proposed. The mechanical behavior of FRP-confined concrete filled steel tube is mainly related to the equivalent confinement effect coefficient before the rupture of FRP. Based on the static equilibrium condition, the equivalent conversion section is adopted; taking as main parameter, the simplified stress-strain model of FRP-confined concrete filled steel tube is established. The predictions of the model agree well with test data.


2019 ◽  
Vol 2019 ◽  
pp. 1-16
Author(s):  
Qin Rong ◽  
Yusheng Zeng ◽  
Lanhui Guo ◽  
Xiaomeng Hou ◽  
Wenzhong Zheng

Results from mechanical tests on thirteen reactive powder concrete- (RPC-) filled circular steel tube (RFCT) columns under monotonic and cyclic axial loading are presented in this paper. The test variables include monotonic and cyclic loadings, confinement coefficient, and diameter of the steel tube. The test results show that the envelope curves of specimens under cyclic loading were similar to the load-deformation curves of the specimens under monotonic loading. Confinement coefficient had a significant influence on the failure modes of RFCT columns. With an increase in confinement coefficient of 0.53 to 0.98, the failure mode transformed from shear failure to compressive failure for specimens under monotonic and cyclic loading. In the elastic stage, no confining effect was provided by the steel tube to the RPC since Poisson’s ratio of steel was larger than the transverse deformation coefficient of RPC. Beyond the elastic stage, the axial compressive strength and ultimate strain of RPC increased significantly due to the confining effect when compared to unconfined RPC. Stress of the steel tube and RPC was investigated by using an elastic-plastic analytical model. Before yielding of the steel tube, stress development in the tube was faster in the longitudinal direction than in the hoop direction. The results of the experiment indicate that the compressive strength of RPC could be predicted by Mander’s model for confined concrete. Based on Mander’s model, an equation is extended to calculate the axial compressive strength of RFCT columns, and the predicted results are in good agreement with the test results. Based on comparative analysis of 180 RFCT columns axial compressive tests, the equation given by EC4 considering the confinement effect can be applied to predict the compressive strength of RFCT columns.


2011 ◽  
Vol 243-249 ◽  
pp. 5541-5546
Author(s):  
Tian Zhi Zhu ◽  
Ming Zhang ◽  
Yan Ying Dong

Fiber reinforced plastics (FRP) has been widely used in structure reinforcement processing. It is a comparatively mature field in computational models of cylindrical axial compressive strength on FRP confined concrete. In this paper, we conduct a possessive analysis on the axial compressive property that is based on the cylindrical stress model of FRP confined concrete, considering the difference among square column section, rectangular column and cylindrical column. Meanwhile, based on cross-sectional area and moment of inertia equivalent principles, we propose an equivalent diameter formula for converting rectangular column section into cylindrical column section. We also introduce sectional influence coefficients to modify ultimate strength and establish a model of ultimate strength for FRP confined concrete. Furthermore, we use the existing experimental data to test the validity and feasibility of the model. Experimental Results of the computational model are quite coincident and consistent with the tests. Computational model can reflect the true characteristics of FRP confined concrete. Therefore, the models proposed in this paper are significant in the practice of construction project.


2013 ◽  
Vol 639-640 ◽  
pp. 1083-1086
Author(s):  
Xiao Kun Wang ◽  
Hua Xin Liu ◽  
Xue Zhi Wang ◽  
Cheng Zhai

More attention has been paid on the technology of BFRP in civil engineering due to it’s unique properties, such as high strength-to-weight radio, good resistance to corrosion and convenient to construction. In order to study the properties of BFRP sheets confined concrete column ,we did it through three groups of columns subjected to axial loading tests and FEM analyses, mainly considering the effect of spacing of straps of BFRP sheets confining concrete column.The results shows that the axial compressive strength and ductility of concrete column winded by BFRP straps have all increased and the process of destruction of concrete column wrapped by BFRP is longer than that of the unconfined concrete column.


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