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.

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 Castellated Steel Beams-A Torsional Analysis

2020 ◽  
Vol 9 (5) ◽  
pp. 536-540
Keyword(s):  
Failure Modes ◽  
Weight Ratio ◽  
High Strength ◽  
Steel Beams ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Moment Capacity ◽  
Flexure Mechanism ◽  
Shear Buckling ◽  
Castellated Beam

Practice of castellated beams (CBs) or perforated beams for several structures speedily gaining petition. This is because of the increased depth in the segment, high strength to weight ratio, light in weight, easy to erect, economical, and stronger. The principal advantages of the castellated beam are an attractive provision, an increase in vertical bending stiffness, & ease of service provision. The CBs is prepared from its virgin sections i.e. I beam by cutting it in a zigzag or any suitable cutting pattern and again rejoined it by welding therefore depth of the resulting section increases. The load-carrying capacity of the parent I section is increased with the same quantity of material and weight, due to an increase in depth of beams. Web post-buckling and lateral-torsional buckling failure occur when these beams are subjected to loading, this is the effect of an increase in depth of the castellated beams. There are five basic failure modes associated with castellated steel beams that need to be taken care of 1) Development of flexure mechanism. 2) Lateral-torsional buckling 3) Vierendeel mechanism 4) rupture of the welded joint in a web post 5) shear buckling of a web post. Therefore, in this research paper, an effort has been made to estimate the torsional moment capacity castellated beam for hexagonal or honeycomb opening with 300, 450, 600 & sinusoidal opening with different fillet radii.

Lateral-torsional buckling of steel beams with slender cross-sections in case of fire

2015 ◽  
Vol 4 (1) ◽  
pp. 52
Author(s):  
Carlos Couto ◽  
Paulo Vila Real ◽  
Nuno Lopes ◽  
Bin Zhao
Keyword(s):  
Cross Sections ◽  
Steel Beams ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling

scholarly journals PARAMETRIC STUDY ON THE LATERAL TORSIONAL BUCKLING OF STAINLESS STEEL I BEAMS WITH CLASS 4 CROSS-SECTIONS IN CASE OF FIRE

2016 ◽  
Author(s):  
Nuno Lopes ◽  
Pedro Gamelas ◽  
Paulo Vila Real
Keyword(s):  
Stainless Steel ◽  
Cross Sections ◽  
Elevated Temperatures ◽  
Numerical Study ◽  
Design Guidelines ◽  
Steel Grade ◽  
Steel Beams ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Steel Members

For predicting the behaviour of beams with thin-walled I sections, named Class 4 in Eurocode 3 (EC3), it is necessary to account for the occurrence of both local and lateral torsional buckling (LTB). These instability phenomena, which are intensified at elevated temperatures, should be accurately considered in design rules. The fire design guidelines for stainless steel members, given in Part 1-2 of EC3, propose the use of the same formulae developed for carbon steel (CS) elements. However, these two materials have different constitutive laws, leading to believe that the use of those formulae should be validated. This work presents a parametric numerical study on the behaviour of stainless steel beams with Class 4 I sections at elevated temperatures. The influences of several parameters such as stainless steel grade, loading type and cross section slenderness are evaluated, and comparisons between the obtained numerical results and EC3 rules are presented.

Flexural Tests on the H-Section Simple Beams with Local Buckling

2011 ◽  
Vol 105-107 ◽  
pp. 1677-1680
Author(s):  
Young Bong Kwon ◽  
Jin Hwan Cheung ◽  
Byung Seung Kong ◽  
Hwan Woo Lee ◽  
Kwang Kyu Choi
Keyword(s):  
Local Buckling ◽  
Bending Moment ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Moment Capacity ◽  
Flexural Members ◽  
Negative Effect ◽  
Large Width ◽  
The Moment ◽  
Flexural Tests

This paper describes a series of flexural tests conducted on the H-section beams fabricated from SM490 plate of thickness 0.6mm with nominal yield stress 315 MPa. Flexural members with large width-to-thickness ratios in the flanges or the web may undergo local buckling before lateral-torsional buckling. The local buckling has a negative effect on the moment capacity based on the lateral-torsional buckling. Simple bending moment capacity formulas for flexural members were calibrated to the test results to account for interaction between local buckling and lateral-torsional buckling. The ultimate flexural strengths predicted by the proposed formulas for direct strength method were compared with the AISC (2005) and Eurocode3 (2003). The comparison showed that the moment formulas proposed can predict conservatively the bending moment capacity of H-section flexural members with local buckling.

Station Square revisited: distortional buckling collapse

1994 ◽  
Vol 21 (3) ◽  
pp. 377-381 ◽  
Author(s):  
Hesham S. Essa ◽  
D. J. Laurie Kennedy
Keyword(s):  
British Columbia ◽  
Steel Beams ◽  
Distortional Buckling ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Finite Element Program ◽  
Buckling Resistance ◽  
Element Program ◽  
The Government ◽  
The Moment

After failure of the roof of the new Save-on-Foods store at the Station Square development in Burnaby, British Columbia, Canada, the government of British Columbia established a commissioner inquiry to investigate the causes of collapse. Collapse was attributed to an undersized W610 × 113 beam in the cantilever-suspended span arrangement and inadequate buckling resistance of the beam-column assembly. The analysis of the lateral-torsional buckling resistance of the collapsed beam in the commissioner's report did not take into account two counteracting effects: the detrimental effect of the load applied above the shear centre and the beneficial effect of the lateral and torsional restraints provided by the open-web steel joists to the collapsed beam. A distortional buckling finite element program is used herein to determine the moment resistance at buckling of the collapsed beam. This program takes into account web distortion, height of load application, inelastic behaviour, and actual restraint conditions. The moment resistance so obtained is in good agreement with the moment applied to the beam at failure. Further analyses show that even with improved restraint details at the critical beam-column location, the beam was inadequate to support the factored loads. A W610 × 195 or even a W610 × 174 beam could be considered adequate. Key words: steel beams, Station Square, lateral-torsional buckling, cantilever-suspended span, web distortion, restraints.

Experimental and Numerical Studies on Lateral-Torsional Buckling of GJ Structural Steel Beams Under a Concentrated Loading Condition

2016 ◽  
Vol 16 (01) ◽  
pp. 1640004 ◽  
Author(s):  
Bo Yang ◽  
Gang Xiong ◽  
Kang Ding ◽  
Shidong Nie ◽  
Weifu Zhang ◽  
...  
Keyword(s):  
Structural Steel ◽  
Parametric Study ◽  
Loading Condition ◽  
Experimental Tests ◽  
Steel Beams ◽  
Design Codes ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Study Results ◽  
Concentrated Loading

GJ structural steel has been applied in many high-rise buildings and large-span structures, such as New CCTV Building and Beijing Olympic Stadium (Birds Nest). However, the design methods of GJ structural steel members are not covered by the current design codes. This paper describes the lateral-torsional buckling behavior of welded sections based on a series of flexural tests performed on H-sections fabricated from GJ structural steel plates. Six steel beams were tested under a concentrated loading condition. It was observed from the experimental tests that lateral-torsional buckling controlled the final failure modes. Numerical simulations of the experimental tests were conducted as well. The numerical simulation results agreed well with the test data. Parametric study was conducted after the validation of the numerical model. Finally, both the experimental test and parametric study results were compared with multiple design codes, including Chinese steel structure design codes (GB50017-2003, GB50017-201X), Eurocode (EC3) and American code (ANSI/AISC360-10). The comparisons indicate that GB50017-201X can predict appropriate flexural strengths of GJ structural steel beams. Also, it is found that the predictions of EC3 are too conservative, while for certain cases ANSI/AISC360-10 predictions are too high for the design flexural strength of GJ structural steel beams.

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