Steel Core in Composite Steel-Concrete Columns

2016 ◽  
Vol 691 ◽  
pp. 195-206
Author(s):  
Juraj Frólo ◽  
Štefan Gramblička
Keyword(s):  
Cross Section ◽  
Design Method ◽  
High Strength ◽  
Concrete Columns ◽  
Steel Tube ◽  
Experimental Investigations ◽  
Composite Columns ◽  
Steel Core ◽  
Composite Steel ◽  
Simplified Design Method

This paper presents some results of theoretical and experimental investigations of composite steel-concrete columns with solid steel profiles - steel cores. Due to absence of simplified design method according to EN 1994-1-1 [1], design of these columns in practice is limited in general. Reasons for this are residual stresses in steel profile caused by fabrication process and limitation of strains in concrete. Recommendations have been determined for simplified design method according to EN 1994-1-1 for composite columns made of high strength concrete filled steel tube with central steel core. Results of experimental research on composite columns with the cross-section made of steel core covered by reinforced concrete are presented.

Slenderness Influence on the Behavior of Composite Columns

2016 ◽  
Vol 691 ◽  
pp. 40-50
Author(s):  
Štefan Gramblička ◽  
Andrea Hrusovska
Keyword(s):  
Cross Sections ◽  
Design Method ◽  
Tall Buildings ◽  
Concrete Columns ◽  
Order Theory ◽  
Second Order ◽  
Order Effects ◽  
Composite Columns ◽  
Steel Members ◽  
Composite Steel

Composite steel and concrete columns have been used in the tall buildings due theirs high-resistance and the possibility to reduce cross sections when we compered composite columns with reinforced concrete columns. There are a lot of types of composite columns. We are concerned with columns, which are completely or partially concrete-encased steel members. In practice, a lot of composite columns are relatively slender and in design the second - order effects will usually need to be included. A partially concrete encased steel cross-section was selected for laboratory tests of composite columns. According to the results of the experiments (total of 18 columns were tested in two series), we analyzed the effects of the second - order theory. The experimental results were compared with theoretical results obtained from the model developed in the non-linear software. The evaluation of the results is also shown in comparison with the general design method according to Eurocode 4, Design of composite steel and concrete structures - Part 1.1 General rules and rules for buildings.

Springback law of high-strength 21-6-9 stainless steel tube in numerical control bending under different process parameters

2015 ◽  
Vol 231 (10) ◽  
pp. 1783-1792 ◽  
Author(s):  
Jun Fang ◽  
Shiqiang Lu ◽  
Kelu Wang ◽  
Zhengjun Yao
Keyword(s):  
Stainless Steel ◽  
Friction Coefficient ◽  
Cross Section ◽  
Process Parameters ◽  
High Strength ◽  
Steel Tube ◽  
Numerical Control ◽  
Stainless Steel Tube ◽  
Outer Diameter ◽  
The Cross

In order to achieve the precision bending deformation, the effects of process parameters on springback behaviors should be clarified preliminarily. Taking the 21-6-9 high-strength stainless steel tube of 15.88 mm × 0.84 mm (outer diameter × wall thickness) as the objective, the multi-parameter sensitivity analysis and three-dimensional finite element numerical simulation are conducted to address the effects of process parameters on the springback behaviors in 21-6-9 high-strength stainless steel tube numerical control bending. The results show that (1) springback increases with the increasing of the clearance between tube and mandrel Cm, the friction coefficient between tube and mandrel fm, the friction coefficient between tube and bending die fb, or with the decreasing of the mandrel extension length e, while the springback first increases and then remains unchanged with the increasing of the clearance between tube and bending die Cb. (2) The sensitivity of springback radius to process parameters is larger than that of springback angle. And the sensitivity of springback to process parameters from high to low are e, Cb, Cm, fb and fm. (3) The variation rules of the cross section deformation after springback with different Cm, Cb, fm, fb and e are similar to that before springback. But under same process parameters, the relative difference of the most measurement section is more than 20% and some even more than 70% before and after springback, and a platform deforming characteristics of the cross section deformation is shown after springback.

Loading Process Simulation of GFRP Tube Filled with Steel-Reinforced High-Strength Concrete Columns Subjected to Eccentric Compression

2011 ◽  
Vol 71-78 ◽  
pp. 4203-4206
Author(s):  
Le Zhou ◽  
Hong Tao Liu
Keyword(s):  
High Strength Concrete ◽  
Slenderness Ratio ◽  
Concrete Strength ◽  
High Strength ◽  
Concrete Columns ◽  
Composite Columns ◽  
Strength Concrete ◽  
Finite Strip Method ◽  
Eccentric Compression ◽  
High Strength Concrete Columns

For the further study of bearing compressive capacity of GFRP tube filled with SHC（steel-reinforced high-strength concrete）columns subjected to eccentric compression, and analysis its whole bearing compressive process under eccentric compression. Based on the flat section assumption finite strip method, the calculating program of bearing eccentric compressive capacity of GFRP tube filled with SHC columns is proposed according to existing retrofit theory and related technical procedures. The relation curves of load-deformation is gotten using this calculating program, at the same time it can get the effect curves of concrete strength, slenderness ratio, eccentricity and containing bone rate to load-deformation. Calculations show that the ultimate bearing compressive capacity of composite column decreases with the increase of slenderness ratio, and elastic stage of component curve gradually shortens and stiffness gradually loses; The ultimate bearing compressive capacity of composite columns decreases with the increase of eccentricity; component ductility improves; the ultimate bearing compressive capacity of composite columns increases with the increase of concrete strength. The calculated results agree well with the experimental results and this study provides a basis for practical design.

Experimental study on the seismic performance of composite columns with an ultra-high-strength concrete-filled steel tube core

2019 ◽  
Vol 23 (4) ◽  
pp. 794-809
Author(s):  
Yong Yang ◽  
Xing Du ◽  
Yunlong Yu ◽  
Yongpu Pan
Keyword(s):  
Energy Dissipation ◽  
Seismic Performance ◽  
High Strength Concrete ◽  
High Strength ◽  
Steel Tube ◽  
Load Bearing Capacity ◽  
Concrete Filled Steel Tube ◽  
Composite Columns ◽  
Strength Concrete ◽  
Steel Strips

The ultra-high-strength concrete-encased concrete-filled steel tube column consists of a concrete-filled steel tube core and a rectangle-shaped reinforced concrete encasement. This article presents the seismic performance analysis of ultra-high-strength concrete-encased concrete-filled steel tube columns subjected to cyclic loading. Based on the measured load-lateral displacement hysteresis curves of six ultra-high-strength concrete-encased concrete-filled steel tube columns and two conventional RC columns, the seismic behaviours, such as the ductility, energy dissipation, stiffness and load-bearing capacity, were analysed. The effects of the arrangement of the stirrups and the layout of the prestressed steel strips on the seismic performance of the composite columns were critically examined. The test results indicated that the ductility and energy dissipation performance of the ultra-high-strength concrete-encased concrete-filled steel tube columns were increased by 74.8% and 162.7%, respectively, compared with the conventional columns. The configuration of the prestressed steel strip increased the ductility of the composite column by 28.9%–63% and increased the energy consumption performance by 160.2%–263.3%. By reducing the stirrup spacing and using prestressed steel strips, the concrete-filled steel tube core columns could be effectively confined, leading to a great enhancement in ductility, energy dissipation, stiffness and load-bearing capacity.

Failure Probability of Short High-Strength Concrete Tied Columns

2003 ◽  
Vol 19 (2) ◽  
pp. 299-309
Author(s):  
Wen-Yao Lu ◽  
Ing-Juang Lin
Keyword(s):  
Monte Carlo ◽  
Cross Section ◽  
Failure Probability ◽  
High Strength Concrete ◽  
High Strength ◽  
Concrete Columns ◽  
Monte Carlo Technique ◽  
Strength Model ◽  
Strength Concrete ◽  
High Strength Concrete Columns

ABSTRACTThis paper aims to investigate the failure probability of short high-strength concrete tied columns using the Monte Carlo technique. The random variables considered in this study are the strength of concrete, the strength of steels, the cross-section dimensions, the location of the steel reinforcement, the variability of strength model and the loads. The results show that the failure probabilities of high-strength concrete columns designed according to the ACI Code are relatively high. The current ACI Code may not be conservative for design of short high-strength concrete tied columns.

scholarly journals Non-linear Analysis of Slender High Strength Concrete Column

2019 ◽  
Vol 5 (7) ◽  
pp. 1440-1451
Author(s):  
Ernesto Fenollosa ◽  
Iván Cabrera ◽  
Verónica Llopis ◽  
Adolfo Alonso
Keyword(s):  
Bearing Capacity ◽  
Cross Section ◽  
Axial Force ◽  
High Strength Concrete ◽  
Bending Moment ◽  
High Strength ◽  
Concrete Columns ◽  
Strength Concrete ◽  
The Moment ◽  
High Strength Concrete Columns

This article shows the influence of axial force eccentricity on high strength concrete columns design. The behavior of columns made of normal, middle and high strength concrete with slenderness values between 20 and 60 under an eccentric axial force has been studied. Structural analysis has been developed by means of software which considers both geometrical and mechanical non-linearity. The sequence of points defined by increasing values of axial force and bending moment produced by eccentricity has been represented on the cross-section interaction diagram until failure for each tested column. Then, diagrams depicting the relationship between failure axial force and column's slenderness have been drawn. The loss of bearing capacity of the member for normal and middle strength columns when compared with the bearing capacity of their cross-section is more noticeable as axial force eccentricity assumes higher values. However, this situation reverses for high strength columns with high slenderness values. On the basis of results obtained, the accuracy level for the moment magnifier method was checked. Despite the good concordance in most of the cases, it was verified that the moment magnifier method leads to excessively tight results for high strength concrete columns with high slenderness values. In these specific cases, a coefficient which amends the column rigidity is proposed so as to obtain safer values.

scholarly journals Investigation of the effect of impact load on concrete-filled steel tube columns under fire

2020 ◽  
Vol 14 (54) ◽  
pp. 317-324
Author(s):  
Ali Golsoorat Pahlaviani ◽  
Ali Mohammad Rousta ◽  
Peyman Beiranvand
Keyword(s):  
Impact Load ◽  
High Strength ◽  
Concrete Columns ◽  
Steel Tube ◽  
Lateral Impact ◽  
Concrete Filled Steel Tube ◽  
Axial Strength ◽  
High Rise ◽  
Working Space ◽  
Cfst Columns

Concrete-filled steel tube (CFST) columns are increasingly used in the construction of high-rise buildings which require high strength and large working space especially at lower stories. As compared to reinforced concrete columns, existence of the exterior steel tube not only bears a portion of axial load but also most importantly provides confinement to the infill concrete.with the confinement provided by the steel tube, axial strength of the infill concrete can be largely enhanced.this paper presents the investigation effect of impact load on concrete-filled steel tube columns under fire by numerical simulations using ABAQUS software.the results indicate that the CFST sections with larger confinement factor ξ=1.23 behaved in a very ductile manner under lateral impact. And the sections with smaller confinement factor ξ=0.44  generally behaved in a brittle mechanism.

Nonlinear Analysis of Eccentric Compression of GFRP Tube Filled with SRHC Columns

2012 ◽  
Vol 476-478 ◽  
pp. 1562-1567
Author(s):  
Le Zhou ◽  
Lian Guang Wang ◽  
Peng Niu ◽  
Hong Bin Nie
Keyword(s):  
Slenderness Ratio ◽  
Concrete Strength ◽  
High Strength ◽  
Concrete Columns ◽  
Composite Columns ◽  
Finite Strip ◽  
Finite Strip Method ◽  
Eccentric Compression ◽  
High Strength Concrete Columns ◽  
Elastic Stage

The whole bearing compressive process under eccentric compression is analyzed for the further study of bearing compressive capacity of GFRP tube filled with SHC（steel-reinforced high-strength concrete）columns subjected to eccentric compression. Based on finite strip method from the plane cross-section assumption, the computation program of bearing eccentric compressive capacity of GFRP tube filled with SHC columns is formulated according to the existing retrofit theory and related technical procedures. The relation curves of load-deformation, as well as the effect curves of concrete strength, slenderness ratio, eccentricity and containing bone rate to load-deformation is obtained by means of this calculating program. Calculations show that the ultimate bearing compressive capacity of composite column decreases with the increase of slenderness ratio, elastic stage of component curve gradually shortens and stiffness gradually loses; The ultimate bearing compressive capacity of composite columns decreases with the increase of eccentricity; component ductility improves; the ultimate bearing compressive capacity of composite columns increases with the increase of concrete strength. The calculated results agree well with the experimental results and provides a basis for practical design

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