scholarly journals Lateral distortional buckling of cellular composite-beams

2018 ◽  
Vol 11 (2) ◽  
pp. 331-356 ◽  
Author(s):  
A. D. PIASSI ◽  
J. V. DIAS ◽  
A. F. G. CALENZANI ◽  
F. C. C. MENANDRO
Keyword(s):  
Flexural Rigidity ◽  
Lateral Displacement ◽  
Limit State ◽  
Composite Beams ◽  
Bottom Flange ◽  
Distortional Buckling ◽  
Critical Moment ◽  
Negative Moment ◽  
Resistant Moment ◽  
Negative Bending

Abstract In the region of negative bending moments of continuous and semi-continuous steel and concrete composite beams, the inferior portion of the steel section is subjected to compression while the top flange is restricted by the slab, which may cause a global instability limit state know as lateral distortional buckling (LDB) characterized by a lateral displacement and rotation of the bottom flange with a distortion of the section’s web when it doesn’t have enough flexural rigidity. The ABNT NBR 8800:2008 provides an approximate procedure for the verification of this limit state, in which the resistant moment to LDB is obtained from the elastic critical moment in the negative moment region. One of the essential parameters for the evaluation of the critical moment is the composite beam’s rotational rigidity. This procedure is restricted only to to steel and concrete composite beams with sections that have plane webs. In this paper, an equation for the calculation of the rotational rigidity of cellular sections was developed in order to determine the LDB elastic critical moment. The formulation was verified by numerical analyses performed in ANSYS and its efficiency was confirmed. Finally, the procedure described in ABNT NBR 8800:2008 for the calculation of the critical LDB moment was expanded to composite beams with cellular sections in a numerical example with the appropriate modifications in geometric properties and rotational rigidity.

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.

Research on Key Issues in Design of Outer-Plated Steel-Concrete Continuous Composite Beams

2012 ◽  
Vol 166-169 ◽  
pp. 414-419
Author(s):  
Li Hua Chen ◽  
Fei Xiao ◽  
Qi Liang Jin
Keyword(s):  
Composite Beam ◽  
Bending Moment ◽  
Longitudinal Shear ◽  
Structural Features ◽  
Composite Beams ◽  
Steel Beam ◽  
Negative Moment ◽  
Key Issues ◽  
Negative Bending ◽  
The Moment

Based on the theoretical analysis and testing results, some key issues in design of outer-plated steel-concrete continuous composite beams are discussed. The influence of the form of steel beam upper flange on the behavior of composite beam is analyzed. The requirements about longitudinal reinforcement strength in the concrete flange of the negative moment region are given. It is suggested that the moment-shear interaction should be neglected when calculating the flexural capacity of outer-plated steel-concrete composite beams under negative bending moment. The behavior of longitudinal shear resistance at the interface between the concrete flange and web of composite beam is studied, and the related calculating formula is put forward based on the structural features of the composite beam.

Analysis of Bearing Capacity of Steel-High Strength Concrete Composite Beams

2013 ◽  
Vol 838-841 ◽  
pp. 661-664
Author(s):  
Liang Li Xiao ◽  
Ming Yang Pan ◽  
Jian Wei Han
Keyword(s):  
Bearing Capacity ◽  
High Strength Concrete ◽  
Influence Factors ◽  
High Strength ◽  
Composite Beams ◽  
Finite Element Program ◽  
Strength Concrete ◽  
Element Program ◽  
Negative Moment ◽  
Negative Bending

It is very crucial to analyze the flexural bearing capacity of the steel-high strength concrete composite beams, but the combination on the flange of steel beam and their bearing capacity is limited with certain inevitability,in addition, in the negative bending regions of continuous composite beams, with the constant increase of load, the process of the whole structure will cause damages in the negative moment region. In order to avoid this kind of damages, we must use general finite element program ANSYS to analyze thebearing capacity of the steel and high strength concrete composite beams. Besides further studying the influence factors of bearing capacity, and ensuring the safety of our engineering performance can be in favor of the engineering structure.

scholarly journals Analysis of Equivalent Flexural Stiffness of Steel–Concrete Composite Beams in Frame Structures

2021 ◽  
Vol 11 (21) ◽  
pp. 10305
Author(s):  
Mu-Xuan Tao ◽  
Zi-Ang Li ◽  
Qi-Liang Zhou ◽  
Li-Yan Xu
Keyword(s):  
Limit State ◽  
Internal Force ◽  
Composite Beams ◽  
Frame Structures ◽  
Flexural Stiffness ◽  
Beam Model ◽  
Vertical Deflection ◽  
Important Indicator ◽  
Vertical Loading ◽  
Negative Moment

Vertical deflection of a frame beam is an important indicator in the limit-state analysis of frame structures, particularly for steel–concrete composite beams, which are usually designed with large spans and heavy loads. In this study, the equivalent flexural stiffness of composite frame beams is analysed to evaluate their vertical deflection. A theoretical beam model with a spring constraint boundary and varied stiffness segments is established to consider the influence of both the rotation restraint stiffness at the beam ends and the cracked section in the negative moment region, such that the inelastic bending deformation of the composite beams can be elaborately described. By an extensive parametric analysis, a fitting formula for evaluating the equivalent flexural stiffness of the composite beams, including the effects of the rotational constraint and the concrete cracking, is obtained. The validity of the proposed formula is demonstrated by comparing its calculation accuracy with those of existing design formulas for analysing the equivalent flexural stiffness of the composite beam members. Moreover, its utility is further verified by conducting non-linear finite element simulations of structural systems to examine the serviceability limit state and the entire process evolution of beam deflections under vertical loading. Finally, to facilitate the practical application of the proposed formula in engineering design, a simplified method to calculate the deflection of composite beams, which utilises the internal force distribution of elastic analysis, is presented based on the concept of equivalent flexural stiffness.

Distortional buckling of I-steel concrete composite beams in negative moment area

2016 ◽  
Vol 20 (1) ◽  
pp. 57-70 ◽  
Author(s):  
Wangbao Zhou ◽  
Shujin Li ◽  
Zhi Huang ◽  
Lizhong Jiang
Keyword(s):  
Composite Beams ◽  
Distortional Buckling ◽  
Negative Moment

scholarly journals Experimental Study on Fatigue Performance of Negative Bending Moment of Steel-Concrete Continuous Composite Box Girder

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Pu Gao ◽  
Kuan Li ◽  
Yuanxun Zheng
Keyword(s):  
Concrete Slab ◽  
Bending Moment ◽  
Composite Beams ◽  
Fatigue Tests ◽  
Reinforcement Ratio ◽  
Fatigue Performance ◽  
Fatigue Load ◽  
Shear Connection ◽  
Negative Moment ◽  
Negative Bending

The experimental work presents results on the fatigue performance of composite beams in the negative moment region and the changes of stiffness and deformation of composite beams under repeated loads; fatigue tests were carried out on two double-layer composite beams. The fatigue performance of composite beams with different reinforcement ratios under complete shear connection and the variation of deflection, strain of the reinforcement, strain of steel beam, and crack growth under fatigue load were obtained. The results showed that the fatigue resistance performance of concrete slab with low reinforcement ratio was much lower than that of concrete slab with high reinforcement ratio whereas, under the fatigue load, the stress of the welding nail in the negative moment region was small and the slip was almost negligible. The degradation of stiffness and the development of cracks were mainly due to the degradation of bond-slip between the concrete and reinforcement. The fatigue failure mode was the fracture of the upper reinforcement in negative moment region. The results obtained in this study are helpful in the design of composite beam.

Elastic Critical Moment of Lateral Distortional Buckling of Castellated Composite Beams under Uniform Hogging Moment

2020 ◽  
Vol 25 (4) ◽  
pp. 04020032
Author(s):  
Carla Cristiane Silva ◽  
Rodrigo Barreto Caldas ◽  
Ricardo Hallal Fakury ◽  
João Victor Fragoso Dias ◽  
Hermes Carvalho
Keyword(s):  
Composite Beams ◽  
Distortional Buckling ◽  
Critical Moment

scholarly journals Experimental and Numerical Studies on the Negative Flexural Behavior of Steel-UHPC Composite Beams

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Xinhua Liu ◽  
Jianren Zhang ◽  
Zihan Cheng ◽  
Meng Ye
Keyword(s):  
Crack Width ◽  
Bending Moment ◽  
Composite Beams ◽  
Flexural Behavior ◽  
Element Analysis ◽  
Conventional Concrete ◽  
Bond Slip ◽  
Cracking Performance ◽  
Negative Moment ◽  
Negative Bending

The cracking of concrete in the negative moment region for a composite beam subjected to a negative bending moment reduces the beam’s strength and stiffness. To improve the cracking performance of composite beams, this paper presents an experimental investigation on applying ultrahigh-performance concrete (UHPC) instead of conventional concrete. Three steel-UHPC composite beams with different forms of joints were designed and tested through a unique rotation angle loading method using a spring displacement control testing setup. The crack distribution, rotation versus crack width, load versus spring displacement, and strains in the UHPC slab and steel girders were measured and studied. Nonlinear finite element analysis using ABAQUS based on the damaged plasticity model of concrete was carried out for comparison with the test results. The experimental and numerical results showed that the use of a UHPC slab can enhance the cracking performance of composite beams. Considering the convenience of construction, a reasonable joint form was suggested, and the appropriate UHPC longitudinal laying length in the negative moment region was proposed to be 0.1 L. Furthermore, a simplified formula for calculating the UHPC crack width was developed based on bond-slip theory.

Elastic Distortional Buckling Analysis of I-Steel Concrete Composite Beam Considering Shear Deformation

2016 ◽  
Vol 16 (08) ◽  
pp. 1550045 ◽  
Author(s):  
Wang-Bao Zhou ◽  
Li-Zhong Jiang ◽  
Shu-Jin Li ◽  
Fan Kong
Keyword(s):  
Shear Deformation ◽  
Composite Beam ◽  
Coupling Effect ◽  
Bottom Flange ◽  
Distortional Buckling ◽  
Related Factors ◽  
Factors Affecting ◽  
Buckling Stress ◽  
Negative Moment ◽  
Applied Forces

Elastic distortional buckling is one of the essential buckling modes of the I-steel concrete composite beam (ISCCB); such buckling often occurs under the gradient of negative moment. The key factors affecting the kind of buckling are the “torsional” and “lateral” restraint stiffnesses of the bottom flange of the beam. This paper investigates the equivalent lateral and torsional restraint stiffnesses of the bottom flange of the ISCCB under the gradient of negative moment. The relations for estimating the lateral and torsional restraint stiffnesses are used to determine the critical distortional buckling stress and associated buckling moment of the beam under the gradient of negative moment. A new method is proposed for assessing the buckling of the elastic-foundation beam, by which the related factors are considered: (1) The coupling effect between the applied forces and lateral/torsional restraint stiffness of the bottom flange of the beam, (2) the effect of gradient of a moment and (3) the effect of shear deformation of the web. The proposed method has been compared with those available by using the data of 15 cases under different loading conditions; the results show that the present method is much more accurate and reliable than the existing ones. The method as proposed herein is recommended for further research in relation to the buckling of the ISCCB.

scholarly journals Distortional Buckling Analysis of Steel-Concrete Composite Girders in Negative Moment Area

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Zhou Wangbao ◽  
Jiang Lizhong ◽  
Kang Juntao ◽  
Bao Minxi
Keyword(s):  
Coupling Effect ◽  
Bending Moment ◽  
Bottom Flange ◽  
Distortional Buckling ◽  
Box Girders ◽  
Composite Girder ◽  
Axial Forces ◽  
Negative Moment ◽  
Applied Forces ◽  
Composite Girders

Distortional buckling is one of the most important buckling modes of the steel-concrete composite girder under negative moment. In this study, the equivalent lateral and torsional restraints of the bottom flange of a steel-concrete composite girder under negative moments due to variable axial forces are thoroughly investigated. The results show that there is a coupling effect between the applied forces and the lateral and torsional restraint of the bottom flange. Based on the calculation formula of lateral and torsional restraints, the critical buckling stress of I-steel-concrete composite girders and steel-concrete composite box girders under variable axial force is obtained. The critical bending moment of the steel-concrete composite girders can be further calculated. Compared to the traditional calculation methods of elastic foundation beam, the paper introduces an improved method, which considers coupling effect of the external loads and the foundation spring constraints of the bottom flange. Fifteen examples of the steel-concrete composite girders in different conditions are calculated. The calculation results show a good match between the hand calculation and the ANSYS finite element method, which validated that the analytic calculation method proposed in this paper is practical.

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