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.

Simulation of Cold Bends by Finite Element Method

2004 ◽  
Author(s):  
M. Behbahanifard ◽  
J. J. R. Cheng ◽  
D. W. Murray ◽  
Joe Zhou ◽  
K. Adams ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Local Buckling ◽  
Element Model ◽  
Shell Elements ◽  
University Of Alberta ◽  
Main Pipe ◽  
Residual Curvature ◽  
Residual Strains ◽  
The Moment

A composite finite element model for cold bend simulation of energy pipelines is presented in this paper. Four-node shell elements with material and geometric nonlinearity are used to model a pipe in straight condition. An elastic pipe, having the same nodal coordinates as the main pipe along with elastic radial links are used as a tool to prevent local buckling and ovalization of the main pipe during the cold bend process. By dividing the elastic pipe into series of rings along the axis of the pipe and by conducting a four-step procedure, residual curvature is developed in a specific segment of a pipe. Based on the proposed concept, different methods of cold bending are discussed and the results are presented. University of Alberta cold bend trials were used to validate the proposed finite element model. The moment-curvature response, pattern of imperfections, and distribution of maximum residual strains are obtained by the finite element model and compared with the test results.

Research on Structural Influencing Coefficient of Moment-Resisting Steel Frames

2011 ◽  
Vol 105-107 ◽  
pp. 937-942
Author(s):  
Cheng Li ◽  
Qiang Gu ◽  
Jun Wang
Keyword(s):  
Strong Earthquake ◽  
Steel Frames ◽  
Local Buckling ◽  
Time History ◽  
Shell Element ◽  
Seismic Code ◽  
Behaviour Factor ◽  
Satisfactory Performance ◽  
Moment Resisting ◽  
Ductility Capacity

This paper is focused on the evaluation of the structural influencing coefficient in multi-story moment-resisting steel frames involving local bucking effect, with due consideration to both their ductility and overstrength. Ductility and overstrength play an important role in keeping satisfactory performance of structures during strong earthquake. Firstly, moment-resisting steel frames of are designed according to Chinese seismic code. Based on the non-linear shell element method, both inelastic time history and pushover analyses has been performed on these steel frames to get the global capacity envelopes. The results show that number of stores and spans have effect on the behaviour factor values, and that the local buckling affects the ductility capacity of steel frames. Finally, based on the findings presented in the article, tentative influencing coefficient values are proposed for moment-resisting steel frames.

Study on Seismic Safety Analysis of Yi Minority Traditional Dwelling in Yunnan

2013 ◽  
Vol 368-370 ◽  
pp. 2021-2026
Author(s):  
Xin Le Li ◽  
Hui Juan Dou
Keyword(s):  
Dynamic Response ◽  
Response Curve ◽  
Three Dimensional ◽  
Element Model ◽  
Seismic Safety ◽  
Moment Resisting ◽  
Dimensional Finite Element ◽  
Design Characteristics ◽  
The Moment ◽  
Three Dimensional Finite Element

Based on Yunnan minority traditional structure, some structural design characteristics are summarized. The three-dimensional finite element model (FEM) of Yi minority dwelling is built.By studying the dynamic characteristics and earthquake responses of Yi minority dwelling,natural frequencies and periods,acceleration dynamic response curve and displacement dynamic response curve are obtained.The equations are applied to calculate the moment resisting capacity of Yi minority dwelling.Depending on the results,the flexible seismic advantages of timber structure for minority structure are verified under the design defense intensity.

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.

scholarly journals Finite Element Analysis of Glass Fiber-Reinforced Polymer-(GFRP) Reinforced Continuous Concrete Beams

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4468
Author(s):  
Hazem Ahmad ◽  
Amr Elnemr ◽  
Nazam Ali ◽  
Qudeer Hussain ◽  
Krisada Chaiyasarn ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Shear Capacity ◽  
Experimental Results ◽  
Beam Specimen ◽  
Fiber Reinforced ◽  
Glass Fiber Reinforced ◽  
Moment Distribution ◽  
The Moment

Fiber-reinforced concrete (FRC) is a competitive solution for the durability of reinforced structures. This paper aims to observe the moment redistribution behavior occurring due to flexural and shear loading in Glass Fiber-Reinforced Polymer- (GFRP) reinforced continuous concrete beams. A rectangular cross-section was adopted in this study with dimensions of 200 mm in width and 300 mm in depth with a constant shear span-to-depth ratio of 3. The reinforcement ratio for the top and bottom were equal at sagging and hogging moment regions. A finite element model was created using Analysis System (ANSYS) and validated with the existing experimental results in the literature review. Based on the literature review, the parametric study was conducted on twelve beam specimens to evaluate the influence of concrete compressive strength, transversal GFRP stirrups ratio, and longitudinal reinforcement ratio on the redistribution of the moment in beams. Several codes and guidelines adopted different analytical models. The Canadian Standards Association (CSA) S806 adopted the modified compression field theory in predicting the shear capacity of the simply supported beams. Recently, various researchers encountered several factors and modifications to account for concrete contribution, longitudinal, and transverse reinforcement. A comparison between the predicting shear capacity of the generated finite element model, the analytical model, and the existing data from the literature was performed. The generated finite element model showed a good agreement with the experimental results, while the beam specimens failed in shear after undergoing significant moment redistribution from hogging to sagging moment region. The moment distribution observed about 21.5% from FEM of beam specimen GN-1.2-0.48-d, while the experimental results achieved 24% at failure load. For high strength concrete presented in beam specimen GH-1.2-0.63-d, the result showed about 20.2% moment distribution, compared to that achieved experimentally of 23% at failure load.

scholarly journals Analytical Benchmark Solutions for Steel Frame Structures Subject to Local Buckling Effects

2000 ◽  
Vol 3 (3) ◽  
pp. 215-229 ◽  
Author(s):  
Philip Avery ◽  
Mahen Mahendran
Keyword(s):  
Finite Element ◽  
Steel Frames ◽  
Local Buckling ◽  
Element Model ◽  
Steel Frame ◽  
Frame Structures ◽  
Steel Frame Structures ◽  
Advanced Analysis ◽  
Shell Finite Element ◽  
Benchmark Solutions

Application of “advanced analysis” methods suitable for non-linear analysis and design of steel frame structures permits direct and accurate determination of ultimate system strengths, without resort to simplified elastic methods of analysis and semi-empirical specification equations. However, the application of advanced analysis methods has previously been restricted to steel frames comprising only compact sections that are not influenced by the effects of local buckling. A research project has been conducted with the aim of developing concentrated plasticity methods suitable for practical advanced analysis of steel frame structures comprising non-compact sections. This paper contains a comprehensive set of analytical benchmark solutions for steel frames comprising non-compact sections, which can be used to verify the accuracy of simplified concentrated plasticity methods of advanced analysis. The analytical benchmark solutions were obtained using a distributed plasticity shell finite element model that explicitly accounts for the effects of gradual cross-sectional yielding, longitudinal spread of plasticity, initial geometric imperfections, residual stresses, and local buckling. A brief description and verification of the shell finite element model is provided in this paper.

scholarly journals Moment Resisting Connection with Curved Endplates: Behaviour Study

2021 ◽  
Vol 11 (4) ◽  
pp. 1520
Author(s):  
Andrej Mudrov ◽  
Antanas Šapalas ◽  
Gintas Šaučiuvėnas ◽  
Kęstutis Urbonas
Keyword(s):  
Experimental Tests ◽  
Steel Beams ◽  
Initial Stiffness ◽  
Flat Plates ◽  
Element Analysis ◽  
Hollow Section ◽  
Moment Resisting ◽  
The Moment ◽  
Circular Hollow Section ◽  
Parametric Finite Element Analysis

This article provides a behaviour analysis of moment resisting joints with curved endplates. This is a new type of connection that can be used for joining steel beams to the circular hollow section (CHS) columns by means of bolts. Some researchers apply the Eurocode model without considering the differences in calculation schemes and assumptions, such as by using the general model of an equivalent T-stub in tension. Consequently, many of the existing behaviour studies are somewhat misleading, thus there is a need for further research. Apart from the absence of analytical methods that are devoted to predicting the initial stiffness and strength of the curved T-stub, other technical difficulties were encountered, such as gaps between the endplate and the column, as well as the initial pre-loading force of the bolts. In the previous studies, endplates were manufactured by rolling flat plates to the precise curvature which resulted in firm contact. In contrast, in this study, endplates were manufactured from a standard CHS tube, which led to significant initial gaps. Meanwhile, in terms of preloading force, it was found that it affected the moment resistance of the joint. This paper discusses problems associated with ongoing researches and presents experimental tests of the two connections. The obtained results were further used in the parametric finite element analysis (FEA) to determine the effect of the gaps and preloading force of the bolts on the moment resistance and initial rotational stiffness of the joint. The results indicate that the behaviour of curved plated connections is exceedingly complex and that the preloading force is the key factor, therefore, it should be controlled.

scholarly journals Flexural Capacity of Locally Buckled Steel I-Beams Under Moment Gradient

2013 ◽  
Vol 7 (1) ◽  
pp. 244-250 ◽  
Author(s):  
Amin Mohebkhah ◽  
Behrouz Chegeni
Keyword(s):  
Local Buckling ◽  
Element Model ◽  
Nonlinear Finite Element ◽  
Flexural Capacity ◽  
Lateral Torsional Buckling ◽  
Limit States ◽  
Torsional Buckling ◽  
Buckled Beams ◽  
Moment Gradient ◽  
Nonlinear Finite Element Model

Lateral-torsional buckling (LTB) and flange local buckling (FLB) are treated as two independent phenomena in AISC-LRFD 360-10 in which the flexural capacity of locally buckled beams is determined as the minimum value obtained for the limit states of LTB and FLB. A 3-D nonlinear finite-element model using ABAQUS is developed in this research to investigate the interactive flexural capacity of steel I-beams with compact web under moment gradient. It was found that the AISC approach is adequate for beams with compact or noncompact sections, however, too conservative for beams with slender flanges representing a considerable interaction between LTB and FLB limit states.

scholarly journals Seismic Design Load for Multi-Story Steel Frames Composed of Expanded Sections

2021 ◽  
Vol 236 ◽  
pp. 02024
Author(s):  
Wu Xiang Xiang
Keyword(s):  
Structural Stability ◽  
Seismic Design ◽  
Steel Frames ◽  
Local Buckling ◽  
Design Load ◽  
Seismic Zones ◽  
Moment Resisting

The steel frames, which are composed of expanded-section columns and beams, have bigger moment-resisting capacity and better structural stability. So that they are broadly applied in multi-story structures in low to medium seismic zones. However, the section is likely to local buckling due to its expanded sections, which decreases the structure ductility. To support its application, how to determine the horizontal seismic design load is studied here.

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