scholarly journals A numerical model with varying passive confinement for circular and elliptical concrete-filled steel tubular columns

2018 ◽  
Author(s):  
Andrés Lapuebla-Ferri ◽  
Cesar Lacuesta ◽  
Manuel L. Romero ◽  
José M. Adam
Keyword(s):  
Numerical Model ◽  
Concrete Strength ◽  
High Strength ◽  
Experimental Tests ◽  
Concrete Core ◽  
Tubular Columns ◽  
Volumetric Deformation ◽  
Cfst Columns ◽  
Plastic Components ◽  
Strength And Ductility

In this work, a non-linear 3D numerical model to study concrete-filled tubular (CFST) columns is presented. The numerical model is capable to consider the passive confinement that occurs in the concrete core of CFST columns, under which an increase in the strength and ductility of the element is expected. Passive confinement is governed by the volumetric deformation of the concrete core and by the increment of concrete strength, so it was necessary to define both aspects in the constitutive model. In the volumetric deformation, the elastic and plastic components were included, the latter by using the Drucker-Prager model. Different values for the angle of dilatancy were defined for normal and high strength concrete. The model was validated by using experimental tests performed on stub columns and eccentrically loaded columns. In addition, different section geometries were tested. According to the results, the model was able to describe the non-uniform confinement that appears in the concrete core of CFST columns. 

scholarly journals Refined strength prediction of concrete 2D bottle-shaped struts

2021 ◽  
Vol 4 (2) ◽  
pp. 111-125
Author(s):  
Abdelrazek E. Ebrahim ◽  
Omar M. Elmeligy ◽  
Salah E. El-Metwally ◽  
Mashhour A. Ghoneim ◽  
Hamed S. Askar
Keyword(s):  
Concrete Strength ◽  
High Strength ◽  
Experimental Tests ◽  
Strength Prediction ◽  
Width Ratio ◽  
Element Analysis ◽  
Minimum Reinforcement ◽  
Strength Concrete ◽  
Bearing Plate ◽  
Effectiveness Factors

For better strength prediction using strut-and-tie models (STM), it is essential to use reliable strength parameters of the model components; e.g., struts, ties, and nodes. Among all the elements of the STM, the strength of the bottle-shaped struts is not well quantified. The purpose of this study is to develop more accurate formulas for the calculation of the effectiveness factors for 2D bottle-shaped struts, that are unreinforced, reinforced with minimum reinforcement, and reinforced with sufficient transverse reinforcement. The nonlinear finite element analysis, with the aid of the software ABAQUS, has been utilized in this study, which has been verified against experimental tests. The study has been carried out for grades of concrete varying from 20 to 100MPa, and for bearing plate to width ratio varying from 0.1 to 0.9. The obtained formulas for the effectiveness factors of bottle-shaped struts are functions of the concrete strength, which is not the case with the ACI 318-19 provisions. These formulas have been verified against experimental tests and have been compared with the ACI 318-19 provisions. The predictions based on these formulas are more accurate than those based on the ACI 318-19 provisions. Also, the results from these formulas are always on the safe side. On the other hand, the ACI 318-19 provisions lead to unsafe results in the case of high-strength concrete and very conservative results for the case of unreinforced struts from normal-strength concrete.

scholarly journals NUMERICAL INVESTIGATION ON CYCLIC BEHAVIOR OF RING-BEAM CONNECTION TO GANGUE CONCRETE FILLED STEEL TUBULAR COLUMNS

2021 ◽  
Keyword(s):  
Cyclic Loading ◽  
Failure Modes ◽  
High Capacity ◽  
High Strength ◽  
Experimental Tests ◽  
Load Level ◽  
Cyclic Behavior ◽  
Tubular Columns ◽  
Earthquake Resistant ◽  
Parametric Studies

As a promising composite structure, gangue concrete filled steel tubular (GCFST) column exhibites favarable characteristics including high strength and economic efficiency. This paper conducted numerical investiagations on structural behavior of a ring-beam connection to GCFST column with concrete beam under cyclic loading. Furthermore, finite element models of column-beam connections were developed using ABAQUS and validated against full-scale experimental tests to identify accuracy of selected modeling approaches. Using these validated models, stress distribution of each component was examined to study the force-transferring mechanism among the components and failure modes of the ring-beam connection. Research study indicated that the ring-beam connection showed a reasonable force-transferring mechanism under cyclic loading and the remarkable earthquake-resistant performance with high capacity and acceptable ductility. Finally, parametric studies were performed to assess the influences of beam-to-column stiffness ratio,steel ratio, axial load level, and concrete compressive strength on connection cyclic behaviors. Parametric studies provided some suggestions and references for the application of the ring-beam connection in various engineering projects.

scholarly journals Experimental Behaviour of Steel Tubular Columns for Varying in Filled Concrete

2017 ◽  
Vol 63 (4) ◽  
pp. 149-160 ◽  
Author(s):  
P. Sangeetha ◽  
R. Senthil
Keyword(s):  
Carrying Capacity ◽  
Slenderness Ratio ◽  
Steel Tube ◽  
Load Carrying Capacity ◽  
Concrete Core ◽  
Composite Action ◽  
Tubular Columns ◽  
Load Carrying ◽  
Cfst Columns ◽  
Quarry Dust

AbstractThis paper investigates the behaviour of axially-loaded tubular columns filled with M20 grade concrete and partially replaced concrete. The parameters varying in the study are slenderness ratio (13.27, 16.58 & 19.9), and normal M20 grade concrete, partially replaced quarry dust and concrete debris. The effects of the various concrete mixes and composite action between the steel tube and the concrete core are studied and a graph visualizing the differences between the load carrying capacity and the axial deflection is plotted. Some of the performance indices like the Ductility Index (DI), Concrete Contribution Ratio (CCR), Confinement Index (θ) and Strength Index (SI) are also evaluated and compared amongst the CFST columns. From the results it has been noted that an increase in the L/D ratio decrease the behaviour of the composite columns irrespective of the in filled materials. The composite action was achieved in the CFST columns filled with partially replaced quarry dust and concrete debris when compared with hollow steel columns. The load carrying capacity of the CFST column increases by 32 % compared with the hollow tubular columns.

scholarly journals Influence of steel tube thickness and concrete strength on the axial capacity of stub CFST columns

2018 ◽  
Author(s):  
Carmen Ibáñez Usach ◽  
David Hernández-Figueirido ◽  
Ana Piquer Vicent
Keyword(s):  
High Strength Concrete ◽  
Concrete Strength ◽  
High Strength ◽  
Steel Tube ◽  
Experimental Program ◽  
Ultimate Capacity ◽  
Strength Concrete ◽  
Axial Capacity ◽  
Thin Walled ◽  
Cfst Columns

In order to study the mechanical response of concrete-filled steel tubular (CFST) columns, several experimental and theoretical studies have been conducted in the last years. However, the influence of thin-walled steel tubes on the axial capacity of these composite columns is not completely stablished, especially when it is combined with high-strength concrete as infill. In this paper, the results of an experimental campaign on 9 concrete-filled steel tubular stub columns subjected to concentric load are presented. Different cross-section shapes are considered in this campaign, i.e. circular, square and rectangular. The influence of the steel tube wall thickness is analysed by including in the tests specimens with thin-walled tubes, whose behaviour needs to be studied in depth given the issues arising when working under compression. The experimental program is designed so the analysis of the results permits to drawn consistent conclusions. For each series, the steel tube thickness is the only geometric parameter modified in order to properly study its effect. Besides, two different concrete strengths were considered for the concrete infill, i.e. normal and high- strength concrete, to observe their effect on the ultimate capacity of the columns. During the tests, the specimens are subjected to axial load and the evolution of the axial displacement with the load is registered. The ultimate capacity of each specimen is obtained and an analysis of the steel tube thickness and concrete strength influence is accomplished. Finally, the study of the dependency of the failure mode on these parameters is carried out.

Behavior of Rectangular Concrete Column Confined with Sisal Fiber Reinforced Polymers (Sisal FRP)

2016 ◽  
Vol 860 ◽  
pp. 140-143 ◽  
Author(s):  
Atipphat Suwattanakorn ◽  
Qudeer Hussain ◽  
Winyu Rattanapitikon ◽  
Amorn Pimanmas
Keyword(s):  
Research Work ◽  
Testing Machine ◽  
High Strength ◽  
Fiber Reinforced Polymers ◽  
Sisal Fiber ◽  
Fiber Reinforced ◽  
Concrete Core ◽  
Reinforced Polymers ◽  
Rectangular Columns ◽  
Strength And Ductility

This research work presents the results of experiment study on the axial behavior of low-high strength concrete rectangular columns confined by Sisal Fiber Reinforced Polymers (Sisal FRP). The objective of this study is investigate the performance of Sisal FRP composites to increase strength and ductility of rectangular columns through external confinement. The research parameter were confinement thickness and strength of concrete core. A total of 16 rectangular columns were tested under Universal Testing Machine (UTM) up to failure point. Test result shown that the external confinement by Sisal FRP are very effective to increase strength and ductility.

The Constitutive Relationship of Concrete Core in Circular Concrete-Filled Steel Tubular Columns

2010 ◽  
Vol 163-167 ◽  
pp. 2063-2067
Author(s):  
Lin Lin Liu ◽  
Yong Qing Tu ◽  
Ying Hua Ye
Keyword(s):  
Numerical Simulation ◽  
Axial Load ◽  
Lateral Pressure ◽  
Confined Concrete ◽  
Constitutive Relationship ◽  
Concrete Core ◽  
Tubular Columns ◽  
Cfst Columns ◽  
Relationship Of ◽  
Concrete Model

Considering the confining mechanism in circular concrete-filled steel tubular (CFST) columns, a volume-based method for dividing the effectively and ineffectively confined area of concrete core and calculating the value of effectively confined coefficient is presented. The constitutive relationship of concrete core is developed by means of modifying the expressions of effective lateral pressure and the descending stage in Mander’s confined concrete model. Numerical simulation of several circular CFST columns under axial load is carried out in ABAQUS. The comparisons between calculated results and experimental results demonstrate that the suggested concrete constitutive relationship is appropriate for the nonlinear analysis of circular CFST columns.

scholarly journals Tests on sea sand concrete-filled stainless steel tubular stub columns

2018 ◽  
Author(s):  
Feiyu Liao ◽  
Chao Hou ◽  
W. J. Zhang ◽  
J. Ren
Keyword(s):  
Stainless Steel ◽  
Concrete Strength ◽  
High Strength ◽  
Normal Concrete ◽  
River Sand ◽  
Concrete Core ◽  
Cross Sectional ◽  
Composite Columns ◽  
Sea Sand ◽  
Stub Columns

This paper presents a series of tests on sea sand concrete-filled stainless steel tubular (SSCFST) stub columns under axial compression, where the main test parameters include type of fine aggregates (river sand, desalted sea sand and sea sand), steel ratio, and concrete strength. The failure mode, axial load versus axial shorten response, cross-sectional strength of the SSCFST specimens are investigated and compared with those of traditional composite columns with normal concrete. The confinement effect between stainless tube and the sea sand concrete is also evaluated. High strength and good ductility was observed for the tested SSCFST stub columns. In general, when being used as the concrete core in a composite column, differences of confinement behaviour between sea sand concrete and normal concrete are not significant, indicating the potential adoption of SSCFST columns in practice.

scholarly journals Research on Carrying Capacity of T-Shaped Stiffened Concrete-Filled Steel Tubular Columns Subjected to Eccentrically Compressive Load

2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Yuanlong Yang ◽  
Xinchen Han ◽  
Bo Nan ◽  
Xin Tang
Keyword(s):  
Mechanical Behavior ◽  
Cross Section ◽  
Parametric Analysis ◽  
Slenderness Ratio ◽  
Concrete Strength ◽  
Engineering Application ◽  
Compressive Load ◽  
Steel Tube ◽  
Tubular Columns ◽  
Cfst Columns

In this paper, in order to further study the mechanical behavior of T-shaped stiffened concrete-filled steel tubular (CFST) columns, numerical programs of eccentrically compressive T-shaped stiffened CFST columns were developed to calculate moment M-ϕ curvature curves of cross section and column. The calculated curves with the numerical programs agree well with the experimental results. A parametric analysis was carried out to calculate M-N correlation curves of cross section and column to investigate influence of concrete strength fck, steel yielding strength fy, steel tube thickness t, slenderness ratio λ, and loading angle θ. On the basis of parametric analysis, simplified resistance models of T-shaped CFST section and column were proposed and verified by the numerical analysis results. The simplified resistance models are reliable to predict the mechanical behavior for engineering application.

scholarly journals IMPROVING THE CALCULATION OF FLEXIBLE CFST-COLUMNS, TAKING INTO ACCOUNT STRESSES IN THE SECTION PLANES

2021 ◽  
Vol 4 (3) ◽  
pp. 41-53
Author(s):  
V. Chepurnenko ◽  
K. Hashhozhev ◽  
S. Yazyev ◽  
Arthur Avakov
Keyword(s):  
Finite Element ◽  
Degrees Of Freedom ◽  
Steel Tube ◽  
Software Systems ◽  
Concrete Core ◽  
Shell Elements ◽  
Tubular Columns ◽  
Cfst Columns ◽  
Deformation Models ◽  
6 Degrees Of Freedom

the article is devoted to a newly developed complex finite element that allows modeling concrete-filled steel tubular columns taking into account the compression of the concrete core from the steel tube, as well as ge-ometric nonlinearity. The derivation of the resolving equations, as well as expressions for the elements of the stiffness matrix, is based on the hypothesis of plane sections. The complex testing of the finite element was performed using the program code written by the authors in the MATLAB language and the ANSYS software, as well as the analysis of the effectiveness of the new FE in comparison with the classical methods of modeling CFST-columns in modern software systems. A significant decrease in the order of the system of FEM equations is demonstrated in comparison with the modeling of CFST-structures in a volumetric formu-lation in existing design complexes using SOLID elements for a concrete core with 3 degrees of freedom in each of the nodes, and SHELL elements for a steel tube with 6 degrees of freedom in each of the nodes, with a comparable accuracy in determining the stress-strain state. The behavior of steel and concrete in the presented work is assumed to be linearly elastic, however, the described calculation method can be generalized to the case of using nonlinear deformation models of materials.

scholarly journals Numerical investigation on slender concrete-filled steel tubular columns subjected to biaxial bending

2018 ◽  
Author(s):  
Ana Espinós ◽  
Vicente Albero ◽  
Manuel L. Romero ◽  
Maximilian Mund ◽  
Inka Kleiboemer ◽  
...  
Keyword(s):  
Numerical Model ◽  
Numerical Investigation ◽  
Experimental Testing ◽  
Experimental Tests ◽  
Major Axis ◽  
Design Guidelines ◽  
Biaxial Bending ◽  
Tubular Columns ◽  
Current Design ◽  
Slender Columns

The behaviour of concrete-filled steel tubular columns under axial compression or combined compression and uniaxial bending has been deeply investigated in past years by means of experimental testing and numerical simulations. However, the behaviour of these columns under biaxial bending has been scarcely investigated, in fact, a very limited number of experimental tests are available for this loading situation. Additionally, the current provisions in EN1994-1-1 for biaxial bending need to be revised, in order to be aligned with the new methods that are being proposed for the new generation of Eurocodes. This paper presents the outcome of a numerical investigation on the load-bearing capacity of slender concrete-filled steel tubular columns subjected to biaxial bending. The focus is on creating and validating a numerical model for room temperature that can predict the behaviour of this type of columns under biaxial bending, which may be used for evaluating the current design guidelines in EN1994-1-1. The numerical model is validated by comparison against experimental tests from the literature, proving that it predicts the ultimate load of slender columns with good accuracy. Different eccentricities about the minor and major axis and different moment ratios are considered, so that this investigation contains cases for both uniaxial and biaxial bending. With the help of this numerical model, the experimental results are extended to generate more cases, in order to assess the accuracy of the current provisions in EN1994-1-1 for concrete-filled steel tubular columns subjected to biaxial bending. 

Sign in / Sign up

Export Citation Format

Share Document