Analysis Methods Investigation of Steel Frames Accounting for Local Buckling

2011 ◽  
Vol 243-249 ◽  
pp. 1391-1395 ◽  
Author(s):  
Lian Kun Wang
Keyword(s):  
Flexural Strength ◽  
Plastic Hinge ◽  
Steel Frames ◽  
Local Buckling ◽  
Shell Elements ◽  
Design Specifications ◽  
Inelastic Analysis ◽  
Analysis Methods ◽  
Eurocode 3 ◽  
Nonlinear Shell

Second-order inelastic analysis should be directly performed in order to overcome the difficulties of the conventional approach, but most of these analyses assume the section to be compact, and do not account for the degradation of the flexural strength caused by local buckling. Since the sections of real structures are not always compact, the analysis should be improved to consider local buckling. The objective of this paper is to investigate the plastic-zone and plastic hinge analysis methods of steel frames accounting for local buckling with nonlinear shell elements and design specifications as AICS-LRFD and Eurocode 3, which may be used as reference for the further study.

A Novel Incremental Iterative Force Recovery Method for Second-Order Beam-Column Elements in Plastic Hinge Analysis of Steel Frames

2021 ◽  
Author(s):  
Yi-Qun Tang ◽  
He Zhu ◽  
Er-Feng Du
Keyword(s):  
Plastic Hinge ◽  
Steel Frames ◽  
Direct Analysis ◽  
High Accuracy ◽  
Second Order ◽  
Single Element ◽  
Recovery Method ◽  
Inelastic Analysis ◽  
Force Recovery ◽  
Plastic Hinge Method

This paper is concerned with an incremental iterative force recovery method in the second-order plastic hinge analysis of steel frames mainly modelled by a single element per member. Second-order beam-column elements are preferred in the direct analysis of steel frames due to their high accuracy and efficiency. However, formulations of these elements are complicated, and therefore they may have a problem of getting element force recovery in inelastic analysis. To overcome this difficulty, a novel incremental iterative force recovery method for second-order beam-column elements is proposed to perform plastic hinge analysis. The proposed method is derived more strictly and has good performance. Also, the section assemblage approach and the refined plastic hinge method are adopted in this study to consider the gradual degradation of section stiffness in the plastic hinge analysis. To verify the accuracy, efficiency and robustness of the proposed method, several benchmark examples are analyzed by the proposed method and compared with solutions reported by early researchers.

A numerical investigation of overstrength and ductility factors of moment resisting steel frames retrofitted with GFRP plates

2014 ◽  
Vol 41 (1) ◽  
pp. 17-31 ◽  
Author(s):  
Mohammad Al Amin Siddique ◽  
Ashraf A. El Damatty ◽  
Ayman M. El Ansary
Keyword(s):  
Steel Frames ◽  
Local Buckling ◽  
Element Model ◽  
Steel Beams ◽  
Shell Elements ◽  
Glass Fiber Reinforced ◽  
Moment Resisting ◽  
Spring System ◽  
The Moment ◽  
Nonlinear Finite Element Model

This paper reports the results of an investigation conducted to assess the effectiveness of using glass fiber reinforced polymer (GFRP) plates to enhance the overstrength and ductility factors of moment resisting steel frames. The GFRP plates are bonded to the flanges of steel beams of the frame with an aim to enhance their local buckling capacities and consequently their ductility. The flexural behaviour of GFRP retrofitted beams is first determined using a nonlinear finite element model developed in-house. In this numerical model, consistent shell elements are used to simulate the flanges and web of the steel beam as well as the GFRP plate. The interface between the steel and the GFRP plate is simulated using a set of continuous linear spring system representing both the shear and peeling stiffness of the adhesive based on values obtained from a previous experimental study. The moment–rotation characteristics of the retrofitted beams are then implemented into the frame model to carry out nonlinear static (pushover) analyses. The seismic performance level of the retrofitted frames in terms of overstrength and ductility factors is then compared with that of the bare frame. The results show a significant enhancement in strength and ductility capacities of the retrofitted frames, especially when the beams of the frame are slender.

scholarly journals Nonlinear Inelastic Analysis of 2D Steel Frames

2020 ◽  
Vol 10 (4) ◽  
pp. 5974-5978 ◽  
Author(s):  
P. C. Nguyen ◽  
B. Le-Van ◽  
S. D. T. V. Thanh
Keyword(s):  
Residual Stresses ◽  
Plastic Hinge ◽  
Steel Frames ◽  
Nonlinear Problems ◽  
Zone Method ◽  
Stability Functions ◽  
Inelastic Analysis ◽  
Fiber Plastic ◽  
And Behavior ◽  
Plastic Hinge Method

In this study, a new method for nonlinear analysis of 2D steel frames, by improving the conventional plastic hinge method, is presented. The beam-column element is established and formulated in detail using a fiber plastic hinge approach. Residual stresses of I-shape sections are declared at the two ends through fibers. Gradual yielding by residual stresses along the member length due to axial force is accounted for by the tangent elastic modulus concept. The P-δ effect is captured by stability functions, whereas the P-Δ effect is estimated by the geometric stiffness matrix. A nonlinear algorithm is established for solving nonlinear problems. The present study predicts the strength and behavior of 2D steel frames as efficiently and accurately as the plastic zone method did.

Advanced Inelastic Analysis of Frame Structures Considering Shearing and Warping Deformations

2011 ◽  
Vol 255-260 ◽  
pp. 268-273
Author(s):  
Lian Kun Wang
Keyword(s):  
Nonlinear Analysis ◽  
Polynomial Interpolation ◽  
Plastic Hinge ◽  
Steel Frames ◽  
Torsion Theory ◽  
Inelastic Analysis ◽  
Cubic Polynomial ◽  
Shearing Deformation ◽  
Plastic Hinge Method ◽  
Interpolation Functions

The paper addresses the derivation of a concentrated plastic-hinge finite element modelling for nonlinear analysis of space steel frames. The interpolation functions considering shearing deformation are adopted and cubic polynomial interpolation functions based on Kollbrnner-Dajdin modified constraint torsion theory are used to consider the warping deformation, with these functions the effect of the secondary shear stress can be taken into account. With the expanded Orbison’s yielding surface, the plastic-hinge method used to do nonlinear analysis of space steel frames is derived by introducing elastic-plastic hinge parameter of element cross section. Numerical examples are presented to illustrate the validity and the universality of the proposed approach and the results show the new model is accurate and suitable for the nonlinear analysis of steel frameworks.

scholarly journals Static inelastic analysis of steel frames with flexible connections

2004 ◽  
Vol 31 (2) ◽  
pp. 101-134 ◽  
Author(s):  
M. Nefovska-Danilovic ◽  
M. Sekulovic
Keyword(s):  
Numerical Model ◽  
Geometric Nonlinearity ◽  
Stiffness Matrix ◽  
Plastic Hinge ◽  
Steel Frames ◽  
Rotational Spring ◽  
Inelastic Analysis ◽  
In Series ◽  
Flexible Connections ◽  
Monotonic Loads

The effects of connection flexibility and material yielding on the behavior of plane steel frames subjected to static (monotonic) loads are presented in this paper. Two types of material nonlinearities are considered: flexible nodal connections and material yielding, as well as geometric nonlinearity of the structure. To account for material yielding, a plastic hinge concept is adopted. A flexible connection is idealized by nonlinear rotational spring. Plastic hinge is also idealized by nonlinear rotational spring attached in series with the rotational spring that accounts for connection flexibility. The stiffness matrix for the beam with flexible connections and plastic hinges at its ends is obtained. To illustrate the validity and accuracy of the proposed numerical model, several examples have been conducted.

Experimental Research and Finite Element Analysis on Behavior of Steel Frame with Semi-Rigid Connections

2010 ◽  
Vol 168-170 ◽  
pp. 553-558
Author(s):  
Feng Xia Li ◽  
Bu Xin
Keyword(s):  
Architectural Design ◽  
Plastic Hinge ◽  
Steel Frames ◽  
Seismic Energy ◽  
Internal Force ◽  
Steel Frame ◽  
Frame Structure ◽  
Element Analysis ◽  
Rigid Deformation ◽  
Steel Frame Structure

Most steel beam-column connections actually show semi-rigid deformation behavior that can contribute substantially to overall displacements of the structure and to the distribution of member forces. Steel frame structure with semi-rigid connections are becoming more and more popular due to their many advantages such as the better satisfaction with the flexible architectural design, low inclusive cost and environmental protect as well. So it is very necessary that studying the behavior of those steel frame under cyclic reversal loading. On the basics of connections experiments the experiment research on the lateral resistance system of steel frame structure has been completed. Two one-second scale, one-bay, two-story steel frames with semi-rigid connections under cyclic reversal loading. The seismic behavior of the steel frames with semi-rigid connections, including the failure pattern, occurrence order of plastic hinge, hysteretic property and energy dissipation, etc, was investigated in this paper. Some conclusions were obtained that by employing top-mounted and two web angles connections, the higher distortion occurred in the frames, and the internal force distributing of beams and columns was changed, and the ductility and the absorbs seismic energy capability of steel frames can be improved effectively.

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