Reduction in the Critical Moment for Lateral Torsional Buckling of Coped Beams

2015 ◽  
Vol 797 ◽  
pp. 3-10 ◽  
Author(s):  
Karolina Brzezińska ◽  
Roman Bijak
Keyword(s):  
Computational Analysis ◽  
Reduction Factor ◽  
Bottom Flange ◽  
The Finite Element Method ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
End Plate ◽  
Analytical Formulas ◽  
Beam Section ◽  
Plate Connection

The paper presents a computational analysis of the effect constructional details of coped connections, assumed to be a fork support in calculations, on the critical LTB moment values. On the basis of analytical formulas by Lindner [1], a formula, having a simple form, was derived for the reduction factor rn for the critical LTB moment. The parameters for the formula were presented in a tabular form, taking into account the beam section (IPE/HEA), the type of beam to end-plate connection (Types 1-3), the load type (q / P) and the way the load is applied (top / bottom flange). The correctness of the derived formula was validated on the basis of the analytical results and the Finite Element Method results obtained with the Abaqus/CAE software. In the program, the beam geometric dimensions and connections were represented as volumetric finite elements. Additionally, the dimensions of the end-plate for IPE and HEA section series were arranged in a systematic manner following the British catalogue.

scholarly journals A comparative study of beam design curves against lateral torsional buckling using AISC, EC and SP

2019 ◽  
Vol 15 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Vera V Galishnikova ◽  
Tesfaldet H Gebre
Keyword(s):  
Steel Structures ◽  
Reduction Factor ◽  
Steel Beams ◽  
Steel Beam ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Vertical Loading ◽  
Beam Design ◽  
Overall Stability

Introduction. Structural stability is an essential part of design process for steel structures and checking the overall stability is very important for the determination of the optimum steel beams section. Lateral torsional buckling (LTB) normally associated with beams subject to vertical loading, buckling out of the plane of the applied loads and it is a primary consideration in the design of steel structures, consequently it may reduce the load currying capacity. Methods. There are several national codes to verify the steel beam against LTB. All specifications have different approach for the treatment of LTB and this paper is concentrated on three different methods: America Institute of Steel Construction (AISC), Eurocode (EC) and Russian Code (SP). The attention is focused to the methods of developing LTB curves and their characteristics. Results. AISC specification identifies three regimes of buckling depending on the unbraced length of the member ( Lb ). However, EC and SP utilize a reduction factor (χ LT ) to treat lateral torsional buckling problem. In general, flexural capacities according to AISC are higher than those of EC and SP for non-compact sections.

scholarly journals Analytical study on lateral torsional buckling of partially encased beams under ISO834 fire exposure

Fire Research ◽  
2016 ◽  
Author(s):  
Ana Belén Ramos-Gavilán ◽  
Paulo Piloto ◽  
Luís Mesquita
Keyword(s):  
Fire Resistance ◽  
Experimental Tests ◽  
Reduction Factor ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Standard Fire ◽  
Resistance Moment ◽  
The Moment ◽  
In Fire ◽  
Simplified Calculation

European standard EN1994-1-2:2005 provides tabulated values and simplified calculation models for assessing fire resistance of composite beams, but does not consider the design checks against lateral torsional buckling under fire. This research presents an analytical method to calculate the buckling resistance moment of laterally unrestrained partially encased beams in fire conditions. The proposal applies a reduction factor for lateral torsional buckling in fire design condition to the moment resistance of the homogenised section at time t, determined by EN1994-1-2:2005. Two finite element models capable to simulate the thermal and mechanical behaviour of partially encased beams are also presented, including the validation against fire tests conducted by Piloto et al. Based on these models, a numerical analysis of partially encased beams with the same geometry and material properties as used in experimental tests is presented, evaluating different load levels when exposed to standard fire ISO834:1999. The numerical results of fire resistance according to standard EN1363- 1:2012 and the numerical ultimate time, when beams suffer instability, are used to validate the proposal, using experimental and analytical heating result according to EN1994-1-2:2005.

scholarly journals Analytical Solution for Lateral-Torsional Buckling of Concrete-Filled Tubular Flange Girders with Torsional Bracing

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Yingchun Liu ◽  
Zhaoming Hang ◽  
Wenfu Zhang ◽  
Keshan Chen ◽  
Jing Ji
Keyword(s):  
Analytical Solution ◽  
Lateral Displacement ◽  
Data Sets ◽  
Torsional Angle ◽  
The Finite Element Method ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Concentrated Load ◽  
Buckling Strength ◽  
Parametric Studies

Concrete-filled tubular flange girders have been used in bridges, and torsional bracings are widely used in them to increase the lateral-torsional buckling strength. This article proposes an analytical solution for the lateral-torsional buckling (LTB) of concrete-filled tubular flange steel girders with torsional bracing under a concentrated load. The modal trial functions of lateral displacement and the torsional angle are expressed by the first six terms of the trigonometric function. By introducing dimensionless parameters, the variational solution of energy for the buckling equation of the LTB of the girders is obtained, and the formula for the dimensionless critical moment of its LTB is derived using 1stOpt based on 32,550 data sets. Compared with the finite element method, the proposed critical formula is highly accurate and can be applied to engineering design. Finally, parametric studies were conducted on the effects of the stiffness of torsional bracing, the span of the girder, and the flange steel ratio.

scholarly journals Lateral torsional buckling capacity of corroded steel beams: A parametric study

2021 ◽  
Vol 1201 (1) ◽  
pp. 012038
Author(s):  
G Kullashi ◽  
S C Siriwardane ◽  
M A Atteya
Keyword(s):  
Cross Sections ◽  
Parametric Study ◽  
Analytical Framework ◽  
Reduction Factor ◽  
Steel Beams ◽  
Uniform Corrosion ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Moment Capacity ◽  
The Moment

Abstract Thickness reduction due to uniform corrosion increases the tendency of lateral torsional buckling (LTB) of open cross-sections and it reduces the moment capacity of the beam. The effect of the various corrosion cases on the LTB moment capacity (M b,rd) of the I-beams are investigated in this paper. An analytical framework for patch corroded I-beams is introduced to provide a guideline for simulating the nonlinear lateral torsional buckling behaviour of patch corroded simple beams. Hence the effect of different corrosion scenarios to reduce the buckling reduction factor (η LT) is investigated by conducting a parametric study. Twelve different beam lengths were considered to obtain different non-dimensional slenderness ratios (λ LT) in this parametric study. The degraded buckling curves were obtained for each corrosion scenarios.

Analytical Solutions of Lateral–Torsional Buckling of Castellated Beams

2016 ◽  
Vol 16 (08) ◽  
pp. 1550044 ◽  
Author(s):  
Boksun Kim ◽  
Long-Yuan Li ◽  
Ashley Edmonds
Keyword(s):  
Analytical Solutions ◽  
Bottom Flange ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Element Analysis ◽  
Web Openings ◽  
Total Potential ◽  
Numerical Studies ◽  
Shear Buckling ◽  
Critical Moments

The majority of the existing literature on the lateral stability of castellated beams deals with experimental and/or numerical studies. This paper presents a comprehensive analytical study of the lateral–torsional buckling of simply supported castellated beams subject to pure bending and/or a uniformly distributed load. Using the principle of total potential energy, analytical expressions for the critical buckling moments and loads are derived and applied for various beam lengths. The three different locations of the applied load are used: At the top flange, shear center and bottom flange. The results show that the influence of web openings on the critical buckling moments and loads are mainly due to the reduction of the torsional constant caused by the web openings. Web shear effects and web shear buckling become important only when the beam is short and the flange is wide. The critical moments and loads will be overestimated or underestimated if the full or reduced section properties are used. The accurate critical moment or load should be calculated based on the average torsional constant of the full and reduced sections rather than simply taking the average of the critical moments or loads calculated from the full and reduced section properties. The present analytical solutions are verified using 3D finite element analysis results.

Experimental Evaluation of Flush End—Plate Connection with Built-up Hybrid Beam Section

2012 ◽  
Vol 15 (2) ◽  
pp. 331-341 ◽  
Author(s):  
P.N. Shek ◽  
M.M. Tahir ◽  
A. Sulaiman ◽  
C.S. Tan
Keyword(s):  
Experimental Evaluation ◽  
End Plate ◽  
Hybrid Beam ◽  
Beam Section ◽  
Plate Connection

scholarly journals The influence of high tensile bolts tightening torque on stress distribution in the bolted connection of rockfall barrier under impact load

2018 ◽  
Vol 219 ◽  
pp. 02014
Author(s):  
Krzysztof Kuliński ◽  
Maciej Major
Keyword(s):  
Stress Distribution ◽  
Impact Load ◽  
Base Plate ◽  
The Finite Element Method ◽  
Bolted Connection ◽  
End Plate ◽  
Rockfall Barrier ◽  
End To End ◽  
Plate Connection ◽  
The Impact

The paper presents the finite element method approach to determine stress distribution in rockfall barrier post with end to end-plate connection, assembled with high tensile bolts under two different types of impact load. For the analysis purposes typical fixed to the foundation, rockfall barrier post is adopted with 2,50 m height and sixty degrees slope to the horizontal ground line. One post end is fixed (welded) to the base plate – anchored to foundation, the second end is supported via retaining rope. The impact load applied exactly in the post mid-height and boulder caught via net in the mid-distance between two consecutive post are discussed. Four different locations of end to end-plate connection are analysed measuring from the fixed support i.e. dimension varies in the range of 0,30 m up to 0,60 m with 0,10 m step. Six high tensile bolts, zinc coated with 12.9 grade strength have been adopted in the connection. The stated boundary problem was solved by means of SolidWorks software.

scholarly journals An Analysis of elastic and inelastic lateral torsional buckling of web-tapered I beams using the finite element method

2019 ◽  
Vol 258 ◽  
pp. 05001
Author(s):  
Paulus Karta Wijaya ◽  
Cecilia Lauw Giok Swan ◽  
Ghassani Sadrina Noor
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
The Other ◽  
The Finite Element Method ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Buckling Mode ◽  
Design Guide ◽  
Element Method ◽  
Critical Moments

Elastic and inelastic lateral torsional buckling of simply web tapered I beam is studied using the finite element method. The length of the beams is 8000 mm for elastic lateral torsional buckling and 4000 mm for inelastic lateral torsional buckling. The depth of cross section at one end is 500 mm and at the other end it is varied. The thickness of the flange is 16 mm and the thickness of the web is 10 mm. The section of the beams is compact. The beams are loaded by end moments. The ratio of end moments at one end and the moments at the other end are varied. The beams are assumed to have geometric imperfection and the distribution of imperfection follows the shape of the first buckling mode of elastic lateral torsional buckling of the beam. The amplitude of the imperfection is taken one milimeter at the top flange in lateral direction. The load is increased until the beams collapse. The ultimate load is considered as the critical moments of the beams. The results of the analysis are compared to nominal lateral torsional buckling moments using the method presented in the AISC Design Guide 25 (Design Guide for web tapered members). It can be concluded that usually the critical moments of the collapse analysis are close to the critical moments of the design guide. But sometimes it is less than the design guide and it means design guide is sometimes is not on the safe side.

scholarly journals Initial rotational stiffness of minor-axis flush end-plate connections

2018 ◽  
Vol 10 (1) ◽  
pp. 168781401774539
Author(s):  
Jianrong Pan ◽  
Shizhe Chen ◽  
Zhan Wang ◽  
Hui Lu
Keyword(s):  
Finite Element ◽  
Minor Axis ◽  
Bottom Flange ◽  
Rotational Stiffness ◽  
Bending Deformation ◽  
End Plate ◽  
Out Of Plane ◽  
Plane Bending ◽  
Plate Connections ◽  
Plate Connection

The semi-rigid performance of minor-axis connections is important in the study of overall framework. Experiments were conducted on minor-axis flush end-plate connections under a monotonic load. Numerical simulations were carried out using the finite-element package ABAQUS and compared with the experimental results. The initial rotational stiffness of the connection was calculated using the equivalent T-stub in tension and EC3 component method, and the calculated veracity is discussed. The results show that under the action of a negative bending moment, the failure modes of the minor-axis flush end-plate connection are the out-of-plane bending deformation of the end-plate, local buckling of the bottom flange of the beam, and bending deformation of the bolts. The minor-axis flush end-plate connection is a typical semi-rigid connection. However, the deformations of the flush end-plate could not be accurately calculated using the equivalent T-stub in the tension of EC3 methods. The initial rotational stiffness calculated using the method was much larger than that obtained using the experiment and finite-element analysis. The equivalent simulation is not appropriate if the out-of-plane bending stiffness of the flush end-plate is not obtained accurately.

Elastic Critical Moment of Lateral-Distortional Buckling of Steel-Concrete Composite Beams under Uniform Hogging Moment

2019 ◽  
Vol 19 (07) ◽  
pp. 1950079 ◽  
Author(s):  
João Victor Fragoso Dias ◽  
Janaina Pena Soares Oliveira ◽  
Adenilcia Fernanda Grobério Calenzani ◽  
Ricardo Hallal Fakury
Keyword(s):  
Numerical Models ◽  
Concrete Slab ◽  
Horizontal Displacement ◽  
Composite Beams ◽  
Bottom Flange ◽  
Distortional Buckling ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Average Deviation ◽  
Critical Moment

Great attention has been given in the last few years to steel–concrete composite beams due to the gains in strength that can be obtained with the small cost of installing a shear connection between the steel profile and the concrete slab. In continuous and semicontinuous composite beams close to the internal supports, hogging bending moments are developed and the compressed bottom flange may buckle laterally in an unstable way known as the lateral-distortional buckling, characterized by a horizontal displacement and twist of the bottom flange with an out-of-plane distortion of the web. In the literature, several formulations were proposed to determine the critical moment for this type of buckling. Among them, some of the most relevant are presented by [K. Roik, G. Hanswille and J. Kina, Solution for the lateral torsional buckling problem of composite beams (in German), Stahlbau 59 (1990)] and [G. Hanswille, J. Lindner and D. Munich, Lateral torsional buckling of composite beams (in German), Stahlbau 67 (1998)]. In the present work, a new procedure is developed to determine the elastic critical moment of lateral–distortional buckling of composite beams under uniform hogging moment. To assess and calibrate this procedure, 7[Formula: see text]772 numerical models were analyzed by the finite element code ANSYS and the results were compared with the ones obtained from the new proposed formulas. The procedure presented excellent agreement with the numerical results, with an average deviation of 2.33% from the computational simulations. The formulations of [K. Roik, G. Hanswille and J. Kina, Solution for the lateral torsional buckling problem of composite beams (in German), Stahlbau 59 (1990)] and [G. Hanswille, J. Lindner and D. Munich, Lateral torsional buckling of composite beams (in German), Stahlbau 67 (1998)] did not lead to such satisfactory results, presenting an average deviation of 12.41% and 16.51%, respectively.

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