THIN-WALLED STEEL TUBULAR COLUMNS WITH UNIFORM AND GRADED THICKNESS UNDER CYCLIC LOADING

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Qusay Al-Kaseasebh ◽  
Iraj H.P Mamaghani
Keyword(s):  
Local Buckling ◽  
Element Model ◽  
Lateral Loading ◽  
Steel Columns ◽  
Tubular Columns ◽  
Aesthetic Appearance ◽  
Significant Strength ◽  
Global Buckling ◽  
Thin Walled ◽  
Graded Thickness

Thin-walled steel tubular circular columns are widely used as cantilever bridge piers due to their geometric efficiency, aesthetic appearance, and high earthquake resistance. However, local buckling, global buckling, or interaction between both is usually the main reason of significant strength and ductility loss in these columns, which eventually leads to their collapse. This paper investigates the behavior of uniform circular (C) and graded-thickness circular (GC) thin-walled steel tubular columns under constant axial and cyclic lateral loading. The GC column with size and volume of material equivalent to the C column is introduced and analyzed under constant axial and cyclic lateral loading. The analysis carried out using a finite-element model (FEM), which considers both material and geometric nonlinearities. The accuracy of the employed FEM is validated based on the experimental results available in the literature. The results revealed that, significant improvements in strength, ductility, and post-buckling behavior of thin-walled steel columns obtained using the GC column.

scholarly journals STRENGTH EVALUATION OF COLD-FORMED STEEL COLUMNS USING THE RESULTS OF FINITE STRIP AND FINITE ELEMENT LINEAR STABILITY ANALYSIS

2009 ◽  
Vol 1 (1) ◽  
pp. 40-43 ◽  
Author(s):  
Luís C. Prola ◽  
Igor Pierin
Keyword(s):  
Stability Analysis ◽  
Linear Stability ◽  
Linear Stability Analysis ◽  
Steel Columns ◽  
Finite Strip ◽  
Strip Method ◽  
Finite Strip Method ◽  
Global Buckling ◽  
Cold Formed Steel ◽  
Thin Walled

Most cold-formed steel columns display open and rather thin-walled cross-sections which mean that their structural behaviour is strongly affected by local and global buckling. Th e local mode, that occurs for shorter profi les, is characterized by (i) the local plate mode (LPM) characterized by the simultaneous flexural buckling of the web and fl anges and (ii) by the distortional mode (DM) characterized by the displacements of flange-stiff ener edges (that remain plane). The global mode occurring for long profi les is characterized by (i) the fl exural mode (FM) characterized by the translation of the whole section in the direction of the major principal axis and (ii) by the fl exural-torsional mode (FTM) characterized by the simultaneous translation and rotation of the whole section. Th e possibility of using the results of linear stability analysis in the national codes of thin-walled cold-formed steel structural elements (for instance, European and Brazilian Codes) arises, i.e. local and global buckling instability modes and corresponding bifurcation stresses determining the ultimate strength of members. Two powerful numerical methods are chosen to perform a linear stability analysis of a cold-formed steel structural member: (i) the Finite Strip Method, (i1) the Semi-Analytical Finite Strip Method (trigonometric functions are used in the approximation of displacement) used for simply supported boundary conditions, (i2) the Spline Finite Strip Method (‘spline’ functions are used in the approximation of displacement) used other boundary conditions and (ii) the Finite Element Method. The linear local and global stability results of for Z, C and rack cold-formed columns are used to obtain ultimate strength through the procedures adopted in the Eurocode 3, Part 1.3 and in the Brazilian Code (NBR 14.762/2001). The obtained numerical estimates by specifi cations are compared with experimental results available in literature.

Optical Measuring Technique for the Investigation of Built-Up Cold-Formed Steel Structural Members

2011 ◽  
Vol 473 ◽  
pp. 343-351 ◽  
Author(s):  
Iveta Georgieva ◽  
Luc Schueremans ◽  
Guido De Roeck ◽  
Lincy Pyl
Keyword(s):  
Local Buckling ◽  
Structural Members ◽  
Distortional Buckling ◽  
Residential Housing ◽  
3D Motion Analysis ◽  
Vertical Displacements ◽  
Global Buckling ◽  
Cold Formed Steel ◽  
Thin Walled ◽  
Displacement Transducers

The construction industry uses cold-formed steel (CFS) sheets in the form of galvanised thin-walled profiles and corrugated sheets. In the past decade, CFS profiles have been competing with their hot-rolled counterparts as primary structural members of industrial halls, office buildings and residential housing of up to 3-4 storeys. The spans and column heights achieved with CFS profiles are ever larger. Due to the large slenderness of these members, adequate strength and stability are necessary, as well as reliability in design. Thin-walled members go through buckling during all stages of their working life. Local buckling appears at loads sometimes much lower than the design load. Distortional buckling seriously reduces the member resistance. It interacts with warping and lateral-torsional buckling, being significant for these asymmetric open sections. To restrict these effects, builders employ double sections - usually two standard cold-formed shapes bolted together to form a built-up section. These sections have the advantages of symmetry, higher stability and strength. The design of built-up members involves many uncertainties - although the European standard includes guidelines on the prediction of local, distortional and global buckling, the partial integrity and interaction between the parts of the composed members is still not studied. To study the actual behaviour, built-up members are tested in bending. An optical device for 3D motion analysis measures the displacement of points of interest on the specimen. Two interacting cameras use parallax to obtain the position of an arbitrary number of reflective markers glued to the specimen. The device tracks the movement of the markers in a 3D coordinate system without any contact with the specimen. Standard displacement transducers measure vertical displacements to validate the results. The paper gives an appraisal of the applicability of the method, a summary of the difficulties faced and the outcome of the test campaign.

Experimental Research on Concrete Filled Thin-Walled Steel Tube Long Columns

2008 ◽  
Vol 400-402 ◽  
pp. 551-557 ◽  
Author(s):  
Bao Zhu Cao ◽  
Yao Chun Zhang ◽  
Yue Ming Zhao
Keyword(s):  
Experimental Research ◽  
Local Buckling ◽  
Steel Tube ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Global Buckling ◽  
Thin Walled ◽  
Relationship Of ◽  
The Relationship ◽  
Theoretical Results

Experimental research on square and octagonal concrete filled thin-walled steel tube long columns of 6 specimens in axial compression and 8 specimens in eccentric compression is undertaken. The relationship of global buckling bearing capacity of the columns and local buckling of the steel tubes is obtained. The test indicates that local buckling occurs in steel tube of each column before it reaches ultimate capacity, and has little effect on global buckling performance. The ultimate load decreases obviously with the increase of slender ratio and eccentricity. The ductility of columns increases with the increase of steel ratio in composite sections. Composite beam element of ANSYS is adopted in the finite element analysis. The theoretical results are agreed well with test..

Numerical Analysis of Debonded Honeycomb Sandwich Structure under Compressive Load

2013 ◽  
Vol 658 ◽  
pp. 227-231
Author(s):  
Tao Zhu ◽  
Jin Long Chen ◽  
Wen Ran Gong
Keyword(s):  
Finite Element ◽  
Local Buckling ◽  
Compressive Load ◽  
Sandwich Panels ◽  
Element Model ◽  
Damage Propagation ◽  
Buckling Behavior ◽  
Honeycomb Sandwich ◽  
Global Buckling ◽  
Honeycomb Sandwich Structure

In this paper, the finite element method (FEM) was applied to predict the local buckling behavior and the debond propagation in honeycomb sandwich panels with face-core debond under in-plane compressive load. The finite element model of the sandwich panel was built, the cohesive element was used to model the adhesive between faces and core, the influence of the debond shape and size on the failure mode, critical buckling load and residual compressive strength of the sandwich panels was investigated, the rule of the damage propagation was summarized. The compression strength of the sandwich panels with through-width face-core debond decreases with increasing debond length. For the panels with central circular debond, when the diameter is less than 15mm, the panels will failure by global buckling and the debond will not grow. When the diameter is greater than 15mm, the panels will failure by local buckling and the critical load strongly decreases with increasing debond diameter. In addition, the direction of debond growth is predominantly perpendicular to the applied load.

scholarly journals Experimental and Analytical Study on Local Buckling Behavior of the Concrete-filled Thin-walled Welded Steel Columns

2020 ◽  
Author(s):  
Deividas Martinavičius ◽  
Mindaugas Augonis ◽  
Mário Rui Tiago Arruda
Keyword(s):  
Analytical Calculation ◽  
Local Buckling ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Element Analysis ◽  
Cross Sectional ◽  
Welded Steel ◽  
Steel Columns ◽  
Analytical Formulas ◽  
Thin Walled

This paper presents an experimental investigation of the concrete filled thin-walled welded steel tubes. Square and rectangular columns are tested with and without the bond between the steel profile and concrete. In order to remove the bond in the latter columns a polyethylene (PE) film is placed inside of the steel profiles. Experimental results are verified via the finite element analysis and compared to the results obtained using the analytical calculation methods. The significance of the steel–concrete bond is evaluated, referring to the differences of the critical loads, ultimate loads and effective cross-sectional areas of the columns with and without the PE film inside and the differences are found to be considerable. It is found that the columns without the film had an up to 47 % higher effective cross-sectional area to full cross-sectional area ratio. The average reduction of the effective cross-sectional area of the column having a poor bond is found to be 12 %. It is also found that the resistance is often overestimated when using the analytical formulas, especially for the columns with the PE film inside.

scholarly journals Experimental Study on Axial Compressive Behavior of Gangue Aggregate Concrete Filled FRP and Thin-Walled Steel Double Tubular Columns

Coatings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1404
Author(s):  
Jian Wang ◽  
Junwu Xia ◽  
Hongfei Chang ◽  
Youmin Han ◽  
Linli Yu ◽  
...  
Keyword(s):  
Stress State ◽  
Bearing Capacity ◽  
Axial Stress ◽  
Local Buckling ◽  
Steel Tube ◽  
Outer Diameter ◽  
Aggregate Concrete ◽  
Tubular Columns ◽  
Inner Diameter ◽  
Thin Walled

In the present paper, the monotonic axial compression test of gangue aggregate concrete filled Fiber reinforced polymer (FRP) and thin-walled steel double tubular columns (DTCC) was carried out, and the gangue aggregate concrete filled FRP tubular columns (CFFT) were designed as a comparison. The main experimental factors were the confinement level of the FRP jacket, the relative diameter ratio (the ratio of the outer diameter of the steel tube to the inner diameter of the FRP jacket), and the different strengths of gangue aggregate concrete. The test results show that the bearing capacity and ductility of gangue aggregate concrete in CFFT were significantly improved. As the local buckling of thin-walled steel tube was effectively inhibited, the load bearing capacity of DTCC was further improved compared with CFFT, but the change of dilation behavior and ductility was insignificant. By analyzing the bi-directional stress state of the steel tube, the confinement level of the external FRP jacket was the most sensitive factor affecting the hoop stress of the steel tube, and the axial stress was obviously weakened under the bi-directional stress state. In addition, with the increase of steel tube diameter, the confinement effect of steel tube in DTCC became more obvious.

scholarly journals Numerical Modelling of Reinforced Concrete Slender Walls Subjected to Coupled Axial Tension–Flexure

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Xiaowei Cheng ◽  
Haoyou Zhang
Keyword(s):  
Reinforced Concrete ◽  
Plastic Hinge ◽  
Element Model ◽  
Lateral Loading ◽  
Design Parameters ◽  
Seismic Behaviour ◽  
High Rise ◽  
Ultimate Deformation ◽  
Axial Tension ◽  
Plastic Hinge Length

AbstractUnder strong earthquakes, reinforced concrete (RC) walls in high-rise buildings, particularly in wall piers that form part of a coupled or core wall system, may experience coupled axial tension–flexure loading. In this study, a detailed finite element model was developed in VecTor2 to provide an effective tool for the further investigation of the seismic behaviour of RC walls subjected to axial tension and cyclic lateral loading. The model was verified using experimental data from recent RC wall tests under axial tension and cyclic lateral loading, and results showed that the model can accurately capture the overall response of RC walls. Additional analyses were conducted using the developed model to investigate the effect of key design parameters on the peak strength, ultimate deformation capacity and plastic hinge length of RC walls under axial tension and cyclic lateral loading. On the basis of the analysis results, useful information were provided when designing or assessing the seismic behaviour of RC slender walls under coupled axial tension–flexure loading.

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