The Experimental Study on the Effect of Expansive Agent on Mechanical Properties of CFST Column with the Creep

2010 ◽  
Vol 163-167 ◽  
pp. 520-523
Author(s):  
Hai Yang Wang ◽  
Xiao Xiong Zha
Keyword(s):  
Bearing Capacity ◽  
Creep Deformation ◽  
Longitudinal Direction ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Obvious Effect ◽  
Expansive Agent ◽  
Cfst Columns

In order to study the influence of expansive agent on the performance of CFST column with the creep due to dead load of the practical construction, in this paper, based on the simulation phase of construction, a series of experiments were conducted to study effect of the expansive agent dosage on the ultimate bearing capacity of CFST columns and the creep deformation in the longitudinal direction. Also the experiments were completed to comparative study on the problem of the recycled aggregate concrete -filled steel tube (RACFST) column. It is found that the ultimate bearing capacity of the CFST column is increased a lot when using the expansive agent, while for the RACFST column it has just a little increase. In contrast, for the RACFST column, there is a greatly increase on the creep deformation in the longitudinal direction, and the more expansive agent dosage the larger deformation, but it is not so obvious effect for general CFST column.

scholarly journals Use of the Gene-Expression Programming Equation and FEM for the High-Strength CFST Columns

2021 ◽  
Vol 11 (21) ◽  
pp. 10468
Author(s):  
Huanjun Jiang ◽  
Ahmed Salih Mohammed ◽  
Reza Andasht Kazeroon ◽  
Payam Sarir
Keyword(s):  
Gene Expression ◽  
Bearing Capacity ◽  
High Strength Concrete ◽  
Gene Expression Programming ◽  
High Strength ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Quick Method ◽  
Strength Concrete ◽  
Cfst Columns

The ultimate strength of composite columns is a significant factor for engineers and, therefore, finding a trustworthy and quick method to predict it with a good accuracy is very important. In the previous studies, the gene expression programming (GEP), as a new methodology, was trained and tested for a number of concrete-filled steel tube (CFST) samples and a GEP-based equation was proposed to estimate the ultimate bearing capacity of the CFST columns. In this study, however, the equation is considered to be validated for its results, and to ensure it is clearly capable of predicting the ultimate bearing capacity of the columns with high-strength concrete. Therefore, 32 samples with high-strength concrete were considered and they were modelled using the finite element method (FEM). The ultimate bearing capacity was obtained by FEM, and was compared with the results achieved from the GEP equation, and both were compared to the respective experimental results. It was evident from the results that the majority of values obtained from GEP were closer to the real experimental data than those obtained from FEM. This demonstrates the accuracy of the predictive equation obtained from GEP for these types of CFST column.

scholarly journals Numerical Study on Confinement Effect and Efficiency of Concentrically Loaded RACFRST Stub Columns

2021 ◽  
Vol 8 ◽  
Author(s):  
Yicen Liu ◽  
Fei Lyu ◽  
Faxing Ding ◽  
En Wang ◽  
Yunlong Xu ◽  
...  
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Steel Tube ◽  
Recycled Aggregate Concrete ◽  
Confinement Effect ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Superposition Method ◽  
Aggregate Concrete ◽  
Stub Columns

The mechanical behaviors of recycled aggregate concrete (RAC) are upgraded by outer steel tube confinement, and the performance of recycled aggregate concrete-filled steel tubular (RACFST) columns is similar to that of the traditional concrete-filled steel tube (CFST) columns. The purpose of this study is to investigate the behaviors of recycled aggregate concrete-filled rectangular steel tubular (RACFRST) stub columns under axial loading. Three-dimensional finite element (FE) models were established, which utilized a triaxial plastic-damage constitutive RAC model considering the replacement ratio of recycled aggregates. The finite element analysis results indicated that the lessened ultimate bearing capacity of RACFRST stub columns compared with their traditional concrete infilled counterparts was mainly due to the weakened confinement effect and confinement efficiency. A simplified formula of the bearing capacity of concentrically loaded RACFRST stub columns was proposed. The cross-sectional stress nephogram was reasonably simplified by the limited state of infilled concrete. The basics of proposed formula were the equilibrium condition and the superposition method. Finally, the formula for the bearing capacity of RACFRST stub columns was evaluated by comparing its accuracy and feasibility to some design formulae proposed by specialists and some design codes of different regions.

scholarly journals Confinement Effect and Efficiency of Concentrically Loaded RACFCST Stub Columns

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 154
Author(s):  
En Wang ◽  
Yicen Liu ◽  
Fei Lyu ◽  
Faxing Ding ◽  
Yunlong Xu
Keyword(s):  
Bearing Capacity ◽  
Ultimate Bearing Capacity ◽  
Recycled Aggregate Concrete ◽  
Confinement Effect ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Replacement Ratio ◽  
Conventional Concrete ◽  
Aggregate Concrete ◽  
Stub Columns

Recycled aggregate concrete-filled steel tubular (RACFST) columns are widely recognized as efficient structural members that can reduce the environmental impact of the building industry and improve the mechanical behavior of recycled aggregate concrete (RAC). The objective of this study is to investigate the behavior of recycled aggregate concrete-filled circular steel tubular (RACFCST) stub columns subjected to the axial loading. Three-dimensional finite element (FE) models were established using a triaxial plastic-damage constitutive model of RAC considering the replacement ratio of recycled aggregates. The FE analytical results revealed that the decreased ultimate bearing capacity of RACFCST stub columns compared with conventional concrete infilled steel tubular (CFST) columns was mainly due to the weakened confinement effect and efficiency. This trend will become more apparent with the larger replacement ratio of recycled aggregates. A practical design formula of the ultimate bearing capacity of RACFCST stub columns subjected to axial load was proposed on the basis of the reasonably simplified cross-sectional stress nephogram at the ultimate state. The derivation process incorporated the equilibrium condition and the superposition theory. The proposed equation was evaluated by comparing its accuracy and accessibility to some well-known design formulae proposed by other researchers and some widely used design codes.

scholarly journals Behavior of Concrete-Filled Steel Tube Columns Subjected to Axial Compression

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Pengfei Li ◽  
Tao Zhang ◽  
Chengzhi Wang
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Ultimate Load ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Plastic Behavior ◽  
Numerical Comparison ◽  
Reinforcing Bars ◽  
Concrete Filled Steel Tube ◽  
Cfst Columns

The behavior of concrete-filled steel tube (CFST) columns subjected to axial compression was experimentally investigated in this paper. Two kinds of columns, including CFST columns with foundation and columns without foundation, were tested. Columns of pure concrete and concrete with reinforcing bars as well as two steel tube thicknesses were considered. The experimental results showed that the CFST column with reinforcing bars has a higher bearing capacity, more effective plastic behavior, and greater toughness, and the elastoplastic boundary point occurs when the load is approximately 0.4–0.5 times of the ultimate bearing capacity. The change of rock-socketed depth and the presence of steel tube will affect the ultimate bearing capacity of rock-socketed pile. The bearing capacities of the rock-socketed CFST columns are lower than those of rock-socketed columns without a steel tube under a vertical load; besides, the greater the rock-socketed depth, the greater the bearing capacity of the rock-socketed piles. In addition, a numerical comparison between the ultimate load and the theoretical value calculated from the relevant specifications shows that the ultimate load is generally considerably greater than the theoretical calculation results.

Experimental Research on Behavior of Axially Square CFRP Steel Tubular Confined Recycled Aggregate Concrete Long Columns

2015 ◽  
Vol 744-746 ◽  
pp. 93-95
Author(s):  
Jiong Feng Liang ◽  
Ping Hua Yi ◽  
Jian Bao Wang
Keyword(s):  
Bearing Capacity ◽  
Coarse Aggregate ◽  
Slenderness Ratio ◽  
Ultimate Bearing Capacity ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Test Results ◽  
Replacement Ratio ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate

Seven axially square CFRP steel tubular confined recycled aggregate concrete long columns were experimentally investigated to study their static behavior. The influence of the slenderness ratio, recycled coarse aggregate replacement ratio, layers of CFRP jackets effect on the performance of axial compression. The test results show that the higher the recycled coarse aggregate content and the slenderness ratio, the greater the specimen ultimate bearing capacity is smaller, and the more the layers of CFRP jackets, the greater the specimen ultimate bearing capacity.

scholarly journals Mechanism Study on the Axial Compressive Performance of Short Square CFST Columns with Different Stiffeners

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Bing Xu ◽  
Fahong Wu ◽  
Guizhong Xu
Keyword(s):  
Bearing Capacity ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Mechanism Study ◽  
Compression Performance ◽  
Compressive Performance ◽  
Combined Action ◽  
Cfst Columns ◽  
Distribution Of Stress ◽  
Core Concrete

In order to limit the disengaging of short square concrete-filled steel tube (CFST) columns and strengthen the combined action of steel tubes and concrete, a reinforcing method of stiffener is put forward in this paper. The axial compression performance and mechanism are studied through experiments, which indicate that (1) the buckling model of stiffening members changes into double wave, (2) stiffeners enforce the constraint in core concrete, (3) stiffeners can effectively improve the ultimate bearing capacity, (4) the stiffeners increase the stress in the middle of the steel tube and improve the distribution of stress for the core concrete, and (5) the direct ribs have more influence on the bearing capacity while ribs with holes have more impact on the deformation of the tube. At the end of the article, a formula for calculating the ultimate bearing capacity is presented, which can bring out a more accurate bearing capacity value.

scholarly journals Seismic Strength and Stiffness for Recycled Aggregate Concrete-Filled Steel Tube Frame

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Xianggang Zhang ◽  
Jianhui Yang ◽  
Yaozong Zhang ◽  
Xiang Gao
Keyword(s):  
Bearing Capacity ◽  
Plastic Hinge ◽  
Single Layer ◽  
Steel Tube ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Aggregate Concrete ◽  
Concrete Filled Steel Tube ◽  
Shear Bearing Capacity ◽  
Strength And Stiffness

To study the seismic strength and stiffness for recycled aggregate concrete-filled steel tube (RACFST) frame, two-frame specimens made up of RACFST column and reinforced recycled aggregate concrete (RAC) beam were used for a seismic test under reversed low-cycle loading. The failure mechanism, hysteresis curve, strength attenuation, and stiffness degradation were determined for the specimens. The design methods for the story shear bearing capacity and stiffness for the single-layer single-span RACFST frame were discussed. It is shown that the seismic design requirements including “strong column weak beam” and “strong shear weak bending” can be met. The hysteresis curves are symmetric and the strength attenuation and rigidity degeneration change significantly, then change a little, and then significantly again under the same displacement. It is possible that the methods including elastic bending moment at the column end, plastic hinge at the column end, and plastic hinge at the column bottom can all be applied to the design calculation of the story shear bearing capacity for the single-layer single-span RACFST frame. The method adopted in this paper can be used to estimate the original elastic layer stiffness of the RACFST frame.

Experimental Studies on Axially Loaded Concrete Columns Confined by Different Materials

2008 ◽  
Vol 400-402 ◽  
pp. 513-518 ◽  
Author(s):  
Yong Chang Guo ◽  
Pei Yan Huang ◽  
Yang Yang ◽  
Li Juan Li
Keyword(s):  
Bearing Capacity ◽  
Glass Fiber ◽  
Failure Modes ◽  
Experimental Studies ◽  
Concrete Columns ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Advantages And Disadvantages ◽  
Axially Loaded ◽  
Normal Strength

The improvement of the load carrying capacity of concrete columns under a triaxial compressive stress results from the strain restriction. Under a triaxial stress state, the capacity of the deformation of concrete is greatly decreased with the increase of the side compression. Therefore, confining the deformation in the lateral orientation is an effective way to improve the strength and ductility of concrete columns. This paper carried out an experimental investigation on axially loaded normal strength concrete columns confined by 10 different types of materials, including steel tube, glass fiber confined steel tube (GFRP), PVC tube, carbon fiber confined PVC tube (CFRP), glass fiber confined PVC tube (GFRP), CFRP, GFRP, polyethylene (PE), PE hybrid CFRP and PE hybrid GFRP. The deformation, macroscopical deformation characters, failure mechanism and failure modes are studied in this paper. The ultimate bearing capacity of these 10 types of confined concrete columns and the influences of the confining materials on the ultimate bearing capacity are obtained. The advantages and disadvantages of these 10 types of confining methods are compared.

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