Experimental Evaluation on Fixed End Supported PFRP Channel Beams and LRFD Approach

2011 ◽  
Vol 105-107 ◽  
pp. 1671-1676 ◽  
Author(s):  
Jaksada Thumrongvut ◽  
Sittichai Seangatith
Keyword(s):  
Experimental Results ◽  
Geometrically Nonlinear ◽  
Vertical Deflection ◽  
Torsional Buckling ◽  
Cross Sectional ◽  
Modes Of Failure ◽  
Flexural Torsional Buckling ◽  
Fixed End ◽  
Structural Behaviors ◽  
Steel Design

In this paper, the experimental results on the fixed end supported PFRP channel beams subjected to three-point loading are presented. The aims of this study are to evaluate the effects of the span (L) on the structural behaviors, the critical buckling moments and the modes of failure of the beams, and to compare the obtained critical buckling moments with those obtained from the modified LFRD steel design equation in order to check the adequacy of the equation. The beam specimens have the cross-sectional dimensions of 76x22x6 mm, with span-to-depth ratio (L/d) ranging from 13 to 52. A total of twenty-six specimens were tested. Based on the experimental results, it was found that the loads versus mid-span vertical deflection relationships of the beams are linear up to the failure. On the contrary, the load versus mid-span lateral deflection relationships are geometrically nonlinear. The general modes of failure are the flexural-torsional buckling. Finally, the modified LFRD equation can satisfactorily predict the critical buckling moment for L/d exceeds 20. However, for L/d < 20, the equation overestimates the critical buckling moment of the beams and more development is needed.

An Experimental Study on the Performance of Fixed-End Supported PFRP Channel Beams under Flexure

2013 ◽  
Vol 702 ◽  
pp. 31-36 ◽  
Author(s):  
Jaksada Thumrongvut ◽  
Sittichai Seangatith
Keyword(s):  
Shear Deformation ◽  
Beam Theory ◽  
Beam Equation ◽  
Vertical Deflection ◽  
Cross Sectional ◽  
Modes Of Failure ◽  
Theory Equation ◽  
Flexural Torsional Buckling ◽  
Fixed End ◽  
Structural Behaviors

The experimental investigation on the fixed-end supported PFRP channel beams subjected to three-point loading is presented. The objectives of this study are to evaluate the effects of the span on the structural behaviors, the critical buckling loads and the modes of failure of the PFRP beams, and to compare the obtained deflections with those obtained from the Timoshenko’s shear deformation beam theory equation in order to check the adequacy of the equation. The beam specimens have the cross-sectional dimensions of 152 43 10 mm with span-to-depth ratio ranging from 16 to 33. A total of twenty-two specimens were performed. Based on the experimental results, it was found that the loads versus mid-span vertical deflection relationships of the beam specimens are linear up to the failure, but the load versus mid-span lateral deflection relationships are geometrically nonlinear. The general modes of failure are the flexural-torsional buckling. Finally, the Timoshenko’s shear deformation beam equation can satisfactorily predict the vertical deflection of the beams within acceptable engineering error.

Influences of Concentric and Eccentric Loads on Buckling of Fixed-End Supported Pultruded FRP Channel Beams

2015 ◽  
Vol 1119 ◽  
pp. 721-725 ◽  
Author(s):  
Jaksada Thumrongvut ◽  
Sittichai Seangatith
Keyword(s):  
Research Work ◽  
Geometrically Nonlinear ◽  
Cross Sectional ◽  
Modes Of Failure ◽  
Cross Sectional Dimension ◽  
Center Position ◽  
The Cross ◽  
Flexural Torsional Buckling ◽  
Fixed End ◽  
Structural Behaviors

This paper presents the results of the experimental research performed on the pultruded FRP (PFRP) channel beams subjected to transversely concentric and eccentric loads. The objectives of the research work are to investigate their structural behaviors and to determine the critical buckling moments and modes of failure of the beams with various span-to-depth ratios and eccentricities. Pultruded beams are fixed-end supported at both ends for major and minor-axis flexure. The beam specimens have the cross-sectional dimension of 102×29×6 mm with span-to-depth ratios, ranging from 20 to 40. A total of 40 mono-symmetric section tests were performed. The effects of vertical load position through the cross-section were studied. Also, shear center position with concentric load and three different eccentricities were investigated ranging from 0 to-3e. The specimens were tested to final buckling. Based upon the results of this study, it is found that the load versus mid-span vertical deflection relationships of the beams are linear up to the failure. On the contrary, the load versus mid-span lateral deflection relationships are geometrically nonlinear. The general mode of failure is the flexural-torsional buckling. The eccentrically loaded specimens are failed at buckling loads lower than their concentric counterparts. Overall, the critical buckling moment decreases as the magnitude of eccentricity increases. Additionally, it is noticed thatL/dratio increases, the critical buckling moment is decreased.

Experimental Investigation on Simply Supported PFRP Channel Beams Subjected to Three-Point Loading

2011 ◽  
Vol 335-336 ◽  
pp. 1321-1326 ◽  
Author(s):  
Sittichai Seangatith ◽  
Jaksada Thumrongvut
Keyword(s):  
Research Work ◽  
Geometrically Nonlinear ◽  
Test Results ◽  
Cross Sectional ◽  
Simply Supported ◽  
Modes Of Failure ◽  
Mode Of Failure ◽  
General Mode ◽  
Flexural Torsional Buckling ◽  
Steel Design

This paper presents the experimental results on the simply supported PFRP channel beams subjected to three-point loading. The objectives of the research work are to investigate the effects of the span (L) of the beams on the behaviors, the critical buckling moments and the modes of failure of the beams, and to compare the obtained critical buckling moments with those obtained from the modified LFRD steel design equation in order to check the adequacy of the equation. The beam specimens have the cross-sectional dimensions of 102×29×6 mm with span-to-depth ratio (L/d) ranging from 20 to 40. A total of ten specimens were tested. Based on the test results, it was found that the load versus mid-span vertical deflection relationships are linear up to the failure, but the load versus mid-span lateral deflection relationships are geometrically nonlinear. The general mode of failure is the flexural-torsional buckling. Finally, the modified LFRD equation can satisfactorily predict the critical buckling moment of the PFRP beams used in this study.

Effects of Changing Double Angles Configuration Used as Braces in Seismic Resisting Systems

2018 ◽  
Vol 763 ◽  
pp. 279-286
Author(s):  
Carlos Bermudez ◽  
Oscar Gutierrez
Keyword(s):  
Compressive Strength ◽  
Slenderness Ratio ◽  
Limit State ◽  
Experimental Results ◽  
Limit States ◽  
Torsional Buckling ◽  
Critical Limit ◽  
Flexural Buckling ◽  
Flexural Torsional Buckling ◽  
Buckling Length

Seismic resisting systems consisting of double angles are used in many parts of the world. Generally, these double angles are arranged in the shape of a T, with a very small distance between them. However, sometimes these angles are distanced and faced in order to improve their mechanical characteristics about the axis of symmetry. In the past, their design was made in the same way as the double angles arranged in a T shape, that is, considering the limit states of flexural buckling and buckling by flexural-torsional, but ignoring the properties of the connectors and their effect on the modified slenderness ratio, as well as the fact that in this case the warping constant is not negligible. These parameters are taken into account in this research in order to study the effects of increasing the distance between the connectors and their possible use as braces in seismic resisting systems. The theoretical results were compared with the experimental results of fifty-seven specimens tested in the laboratory of structures of the Universidad Nacional de Colombia – Sede Manizales. The models were classified according to the main angles, the connectors, the total lengths, and the width of separation. All of them were subjected to axial compressive stress, with free rotation at both ends. Three identical specimens of each model were constructed. The flexural buckling length about x-axis was limited to two meters in all specimens tested whereas the flexural bucking length about y-axis and flexural-torsional buckling length were not limited, i.e. these lengths are equivalent to the total length of each specimen tested. This in order that the critical limit state was to be the flexural-torsional buckling as a function of the torsional buckling term in Z, except in the models of class 2 in which this induced condition was not reached. This was proposed to better evaluate the torsional buckling term in Z. The experimental results show that the nominal compressive strength for the flexural-torsional buckling limit state, when it is governed by torsion, is undervalued. A new methodology is proposed for the calculation of the nominal compressive strength for the flexural-torsional buckling limit state, when it is governed by torsion.

Experimental Investigation on Axially Loaded PFRP Compression Members Having Double C-Sections

2014 ◽  
Vol 548-549 ◽  
pp. 510-514
Author(s):  
Sittichai Seangatith ◽  
Jaksada Thumrongvut ◽  
Chanon Chatwiwat
Keyword(s):  
Experimental Investigation ◽  
Research Work ◽  
Test Results ◽  
Cross Sectional ◽  
Modes Of Failure ◽  
Linear Behavior ◽  
Compression Members ◽  
Axially Loaded ◽  
Structural Behaviors ◽  
Structural Plastics

This paper presents the results of an experimental investigation on axially loaded PFRP compression members having double C-sections with pinned-pinned supports. The objectives of this research work are to investigate their structural behaviors and modes of failure and to propose their design equations. The specimens were built from single PFRP C-section, having three cross-sectional dimensions of 76×22×6 mm, 102×29×6 mm and 152×43×10 mm. A total of 42 specimens with slenderness ratios ranging from 21 to 168 were tested. The compression members can be classified as short and long. The short compression members have linear behavior up to 90% to 95% of the ultimate crushing loads. The long compression members have linear behavior up to 80-90% of the flexural buckling loads. By comparing and fitting the test results with the design equations as presented in the ASCE Structural Plastics Design Manual, the design equations that can be used to predict the ultimate compressive stress of the compression members were proposed.

scholarly journals Experimental and Numerical Study on the Lateral-Torsional Buckling of Steel C-Beams with Variable Cross-Section

Metals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 941
Author(s):  
Ida Mascolo ◽  
Mariano Modano ◽  
Antimo Fiorillo ◽  
Marcello Fulgione ◽  
Vittorio Pasquino ◽  
...  
Keyword(s):  
Cross Section ◽  
Numerical Study ◽  
Numerical Approach ◽  
Computational Effort ◽  
Experimental Results ◽  
Variable Cross ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Cross Sectional ◽  
Thin Walled

Metallic thin-walled beams with continuously varying cross-sections loaded in compression are particularly sensitive to instability problems due to lateral-torsional buckling. Such a phenomenon depends on several parameters, including the cross-sectional properties along the entire length, material properties, load distribution, support, and restraint conditions. Due to the difficulty of obtaining analytic solutions for the problem under consideration, the present study takes a numerical approach based on a variational formulation of the lateral-torsional buckling problem of tapered C-beams. Numerical simulations are compared with experimental results on the buckling of a physical model of at thin-walled beam with uniformly varying cross-section, with the aim of assessing the accuracy of the proposed approach. The good agreement between numerical and experimental results and the reduced computational effort highlight that the proposed variational approach is a powerful tool, provided that the geometry of the structure and the boundary conditions are accurately modeled.

Flexural-Torsional Buckling of Pultruded Fiber-Reinforced Polymer Angle Beams under Eccentric Loading

2020 ◽  
Vol 982 ◽  
pp. 201-206
Author(s):  
Jaksada Thumrongvut ◽  
Natthawat Pakwan ◽  
Samaporn Krathumklang
Keyword(s):  
Buckling Load ◽  
Fiber Reinforced Polymer ◽  
Width Ratio ◽  
Fiber Reinforced ◽  
Torsional Buckling ◽  
Eccentric Load ◽  
Buckling Loads ◽  
Reinforced Polymer ◽  
Cross Sectional Dimension ◽  
Flexural Torsional Buckling

In this paper, the experimental study on the pultruded fiber-reinforced polymer (pultruded FRP) angle beams subjected to transversely eccentric load are presented. A summary of critical buckling load and buckling behavior for full-scale flexure tests with various span-to-width ratios (L/b) and eccentricities are investigated, and typical failure mode are identified. Three-point flexure tests of 50 pultruded FRP angle beams are performed. The E-glass fibre/polyester resin angle specimens are tested to examine the effect of span-to-width ratio of the beams on the buckling responses and critical buckling loads. The angle specimens have the cross-sectional dimension of 76x6.4 mm with span-to-width ratios, ranging from 20 to 40. Also, four different eccentricities are investigated, ranging from 0 to ±2e. Eccentric loads are applied below the horizontal flange in increments until beam buckling occurred. Based upon the results of this study, it is found that the load and mid-span vertical deflection relationships of the angle beams are linear up to the failure. In contrast, the load and mid-span lateral deflection relationships are geometrically nonlinear. The general mode of failure is the flexural-torsional buckling. The eccentrically loaded specimens are failed at critical buckling loads lower than their concentric counterparts. Also, the quantity of eccentricity increases as buckling load decreases. In addition, it is noticed that span-to-width ratio increases, the buckling load is decreased. The eccentric location proved to have considerable influence over the buckling load of the pultruded FRP angle beams.

scholarly journals The effect of flexural–torsional buckling on the stability of timber members: a case study

2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Osama A. B. Hassan
Keyword(s):  
Axial Compression ◽  
Bending Moment ◽  
List Type ◽  
Torsional Buckling ◽  
Solution Methods ◽  
Simplified Solution ◽  
The Stability ◽  
Flexural Torsional Buckling ◽  
Building Engineering

Abstract This study investigates the stability of timber members subjected to simultaneously acting axial compression and bending moment, with possible risk for torsional and flexural–torsional buckling. This situation can occur in laterally supported members where one side of the member is braced but the other side is unbraced. In this case, the free side will buckle out of plane while the braced side will be prevented from torsional and flexural–torsional buckling. This problem can be evident for long members in timber-frame structures, which are subjected to high axial compression combined with bending moments in which the member is not sufficiently braced at both sides. This study is based on the design requirement stated in Eurocode 5. Solution methods discussed in this paper can be of interest within the framework of structural and building Engineering practices and education in which the stability of structural elements is investigated. Article Highlights This case study investigates some design situations where the timber member is not sufficiently braced. In this case, a stability problem associated with combined torsional buckling and flexural buckling can arise. The study shows that the torsional and/or flexural–torsional buckling of timber members can be important to control in order to fulfil the criteria of the stability of the member according to Eurocode 5 and help the structural engineer to achieve safer designs. The study investigates also a simplified solution to check the effect of flexural torsional buckling of laterally braced timber members.

Study of flexural–torsional buckling behaviour of 6061-T6 aluminium alloy unequal-leg angle columns

2021 ◽  
Vol 164 ◽  
pp. 107821
Author(s):  
Ying Zhang ◽  
Yidu Bu ◽  
Yuanqing Wang ◽  
Zhongxing Wang ◽  
Yuanwen Ouyang
Keyword(s):  
Aluminium Alloy ◽  
Torsional Buckling ◽  
Flexural Torsional Buckling
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