CONCRETE-FILLED TUBULAR COLUMNS: PART 2 — COLUMN ANALYSIS

This paper is concerned with an analytical model for column analysis of concrete-filled tubular beam-columns subjected to the combined action of axial load and monotonic or cyclic bending. A method of segmentation is adopted in the analysis of beam-columns. The flexural and axial rigidities of the beam-column segments are derived from M–P–φ and M–P–ε relations obtained through fibre-analysis explained in Part 11 of the paper. Geometric and material nonlinearities are taken into account and incremental equilibrium equations are formulated based on an updated Lagrangian formulation. An incremental-iterative Newton–Raphson iteration technique is adopted to obtain the solution of the equations. The limitation of Newton–Raphson technique in approaching the limit points is overcome by using a generalized stiffness parameter, thereby tracing the post-buckling response. The accuracy of the model is verified by comparing the results with the experimental values available in published literature.

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Post-Buckling Analysis of Heavy Columns with Application to Marine Risers

Journal of Ship Research ◽

10.5957/jsr.1985.29.3.162 ◽

1985 ◽

Vol 29 (03) ◽

pp. 162-169

Author(s):

Theodore Kokkinis ◽

Michael M. Bernitsas

Keyword(s):

Boundary Conditions ◽

Small Strain ◽

Equilibrium Path ◽

Drilling Mud ◽

Tubular Columns ◽

Buckling Behavior ◽

Post Buckling ◽

Combined Action ◽

Raphson Iteration ◽

Good Agreement

The post-buckling behavior of heavy tubular columns following static instability under the combined action of weight, tension/compression at the top, and fluid static pressure forces in the gravity field is studied. A two-dimensional nonlinear small-strain large-deflection model of the column is derived, consisting of an integrodifferential equilibrium equation and two end rotation conditions. The equation of equilibrium is discretized using a finite-element method. An approximate solution valid in the neighborhood of the bifurcation point and an incremental solution are used to determine the secondary equilibrium path. The results of both methods are corrected by Newton-Raphson iteration. Conditions for unstable initial post-buckling behavior and existence of limit points on the secondary equilibrium path are presented. The numerical solution is applied to the problem of the elastica and is found to be in good agreement with the analytical solution. The secondary equilibrium path for a 500-m-long (1640 ft) marine drilling riser is calculated for two sets of boundary conditions and various values of the drilling mud density. The effect of the drilling mud density and the boundary conditions on the riser's post-buckling behavior is discussed.

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Equilibrium considerations of the updated Lagrangian formulation of beam-columns with natural concepts

International Journal for Numerical Methods in Engineering ◽

10.1002/nme.1620241108 ◽

1987 ◽

Vol 24 (11) ◽

pp. 2119-2141 ◽

Cited By ~ 25

Author(s):

Marcelo Gattass ◽

John F. Abel

Keyword(s):

Lagrangian Formulation ◽

Beam Columns ◽

Updated Lagrangian Formulation ◽

Updated Lagrangian

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Finite Element Modeling of Metal Forming Processes Using Updated Lagrangian Formulation

Engineering Materials and Processes - Modeling of Metal Forming and Machining Processes ◽

10.1007/978-1-84800-189-3_6 ◽

2008 ◽

pp. 345-423

Keyword(s):

Finite Element ◽

Finite Element Modeling ◽

Metal Forming ◽

Lagrangian Formulation ◽

Element Modeling ◽

Updated Lagrangian Formulation ◽

Updated Lagrangian

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Behavior of the T-Shaped Concrete-Filled Steel Tubular Columns after Elevated Temperature

Advances in Civil Engineering ◽

10.1155/2021/6638736 ◽

2021 ◽

Vol 2021 ◽

pp. 1-20

Author(s):

Xianglong Liu ◽

Jicheng Zhang ◽

Hailin Lu ◽

Ning Guan ◽

Jiahao Xiao ◽

...

Keyword(s):

Elevated Temperature ◽

Bearing Capacity ◽

Failure Modes ◽

Shear Failure ◽

Element Model ◽

Ultimate Bearing Capacity ◽

Steel Tubes ◽

Tubular Columns ◽

Short Columns ◽

Experimental Values

The mechanical properties of T-shaped concrete-filled steel tubular (TCFST) short columns under axial compression after elevated temperature are investigated in this paper. A total of 30 TCFST short columns with different temperature (T), steel ratio (α), and duration of heating (t) were tested. The TCFST column was directly fabricated by welding two rectangular steel tubes together. The study mainly investigated the failure modes, the ultimate bearing capacity, the load-displacement, and the load-strain performance of the TCFST short columns. Experimental results indicate that the rectangular steel tubes of the TCFST column have deformation consistency, and the failure mode consists of local crack, drum damage, and shear failure. Additionally, the influence of high temperature on the residual bearing capacity of the TCFST is significant, e.g., a higher temperature can downgrade the ultimate bearing capacity. Finally, a finite element model (FEM) is developed to simulate the performance of the TCFST short columns under elevated temperature, and the results agree with experimental values well. Overall, this investigation can provide some guidance for future studies on damage assessment and reinforcement of the TCFST columns.

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NONLINEAR GENERALIZED BEAM THEORY FOR COLD-FORMED STEEL MEMBERS

International Journal of Structural Stability and Dynamics ◽

10.1142/s0219455403001002 ◽

2003 ◽

Vol 03 (04) ◽

pp. 461-490 ◽

Cited By ~ 74

Author(s):

N. SILVESTRE ◽

D. CAMOTIM

Keyword(s):

Numerical Technique ◽

Beam Theory ◽

Equilibrium Equations ◽

Steel Members ◽

Mode Decomposition ◽

Nonlinear Equilibrium ◽

Geometrical Imperfections ◽

Post Buckling ◽

Cold Formed Steel ◽

Generalized Beam Theory

A geometrically nonlinear Generalized Beam Theory (GBT) is formulated and its application leads to a system of equilibrium equations which are valid in the large deformation range but still retain and take advantage of the unique GBT mode decomposition feature. The proposed GBT formulation, for the elastic post-buckling analysis of isotropic thin-walled members, is able to handle various types of loading and arbitrary initial geometrical imperfections and, in particular, it can be used to perform "exact" or "approximate" (i.e., including only a few deformation modes) analyses. Concerning the solution of the system of GBT nonlinear equilibrium equations, the finite element method (FEM) constitutes the most efficient and versatile numerical technique and, thus, a beam FE is specifically developed for this purpose. The FEM implementation of the GBT post-buckling formulation is reported in some detail and then employed to obtain numerical results, which validate and illustrate the application and capabilities of the theory.

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