Axial compressive behavior of reactive powder concrete-filled circular steel tube stub columns

2019 ◽  
Vol 153 ◽  
pp. 42-54 ◽  
Author(s):  
Qiuwei Wang ◽  
Qingxuan Shi ◽  
Eric M. Lui ◽  
Zhaodong Xu
Keyword(s):  
Steel Tube ◽  
Reactive Powder Concrete ◽  
Compressive Behavior ◽  
Circular Steel Tube ◽  
Reactive Powder ◽  
Stub Columns

scholarly journals Comparative Study on the Axial Compression and Bearing Capacity of Reactive Powder Concrete-Filled Circular Steel Tube

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Mingyang Chen ◽  
Xiaomeng Hou
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Limit Equilibrium ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Reactive Powder Concrete ◽  
Fiber Volume ◽  
Loading Mode ◽  
Circular Steel Tube ◽  
Reactive Powder

Reactive powder concrete (RPC) was confined by the circular steel tube to obtain the required ductility. The axial compression test results of 139 columns from different scholars were collated and compared to study the axial compression and bearing capacity of a reactive powder concrete-filled circular steel tube, of which the confining coefficient is 0.057–2.312 and the RPC strength is 76.6–178.2 MPa. Load-displacement curves have been categorized into four stages: (1) elastic; (2) elastic-plastic; (3) descending; and (4) strengthening. The failure mode can be divided into three types according to the different confining coefficients as (1) wall buckling; (2) diagonal shear; and (3) drum-shaped. The confining coefficient, core RPC strength, steel fiber volume, steel tube D/t ratio, and loading mode on the ultimate bearing capacity were analyzed. The results showed the confining coefficient to be the main factor affecting ultimate bearing capacity. The equation for determining ultimate bearing capacity was established based on the limit equilibrium theory, with the lateral confining coefficient of RPC (k) determined to be 2.86, less than that of normal concrete at 4.1. Based on the experimental analysis results and China’s “Design and Construction Code for Concrete-Filled Steel Tube Structure” (CECS 28-2012), the design proposal for an RPC-filled steel tube was recommended.

Predictions of residual carrying-capacities for fire and near-field blast-damaged reactive powder concrete-filled steel tube columns

2018 ◽  
Vol 9 (4) ◽  
pp. 525-553 ◽  
Author(s):  
Wanxiang Chen ◽  
Zixin Zhou ◽  
Huihui Zou ◽  
Zhikun Guo
Keyword(s):  
Carrying Capacity ◽  
Large Scale ◽  
Blast Resistance ◽  
Near Field ◽  
Theoretical Method ◽  
Steel Tube ◽  
Reactive Powder Concrete ◽  
Concrete Filled Steel Tube ◽  
Damage Indices ◽  
Reactive Powder

An approximate approach is developed to estimate the residual carrying-capacities of fire and near-field blast-damaged reactive powder concrete-filled steel tube columns. The single-degree-of-freedom model is employed to calculate the initial deflections of fire-damaged reactive powder concrete-filled steel tube columns subjected to axial and blast-induced transverse loads, and then a modified formula including double coefficient is further proposed to predict the ultimate resistance. Then, a series of blast-resistance and load carrying-capacity tests on six large-scale reactive powder concrete-filled steel tube columns are conducted to validate the suitability of theoretical method presented in this article. Blast tests demonstrate that the blast-resistances of reactive powder concrete-filled steel tube columns are more sensitive to fire durations than to scale distances. In addition, it is indicated that ISO-834 standard fire exposures cause significant degradations of material properties and have remarkable effects on the residual carrying-capacities of reactive powder concrete-filled steel tube columns. No local bucking and burst could be observed in the residual carrying-capacity tests; also, there are no visible hinge-like deformations in the mid-span area, and the excellent fire-resistances and blast-resistances of reactive powder concrete-filled steel tube columns are experimentally verified. Analytical results show that the predicted axial load capacities of six reactive powder concrete-filled steel tube columns are in good agreement with experimental data. All damage indices of the test specimens are within 0.8, meaning only minor to severe damage is done to the reactive powder concrete-filled steel tube column during fire and blast attacks, which is consistent with the test results.

Concrete filled double circular steel tube (CFDCST) stub columns

2017 ◽  
Vol 135 ◽  
pp. 68-80 ◽  
Author(s):  
Talha Ekmekyapar ◽  
Baraa J.M. AL-Eliwi
Keyword(s):  
Steel Tube ◽  
Circular Steel Tube ◽  
Stub Columns

scholarly journals Response of RPC-Filled Circular Steel Tube Columns under Monotonic and Cyclic Axial Loading

2019 ◽  
Vol 2019 ◽  
pp. 1-16
Author(s):  
Qin Rong ◽  
Yusheng Zeng ◽  
Lanhui Guo ◽  
Xiaomeng Hou ◽  
Wenzhong Zheng
Keyword(s):  
Compressive Strength ◽  
Cyclic Loading ◽  
Axial Loading ◽  
Steel Tube ◽  
Test Results ◽  
Confining Effect ◽  
Circular Steel Tube ◽  
Axial Compressive Strength ◽  
Reactive Powder ◽  
Elastic Stage

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.

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

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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