scholarly journals Effective Flange Width for Composite Steel Beams

2011 ◽  
Vol 7 (2) ◽  
pp. 28 ◽  
Author(s):  
T. Salama ◽  
H.H. Nassif

 The effective flange width is a concept proposed by various codes to simplify the computation of stress distribution across the width of composite beams. Questions have been raised as to the validity of the effective slab width provisions, since they have a direct effect on the computed ultimate moment as well as serviceability limit states such as deflection, fatigue, and overloading. The objective of this paper is to present results from an experimental and analytical investigation to determine the effective slab width in steel composite beams. The Finite Element Method (FEM) was employed for the analysis of composite steel-concrete beams having variable concrete flange widths. Results were compared to those from tests performed on eight beams loaded to failure. Beam test specimens had variable flange width and various degrees of composite action (shear connectors). The comparison presented in terms of the applied load versus deflection, and strain in the concrete slab show that the AISC-LRFD code is conservative and underestimates the width active. Based on a detailed parametric study an equation for the calculation of the effective flange width is recommended. 

Author(s):  
Cosmin G Chiorean ◽  
Marius S Buru

This paper presents an efficient computer method for large deflection distributed plasticity analysis of 3D semi-rigid composite steel-concrete frameworks. A novel second-order inelastic flexibility-based element has been developed by combining the Maxwell-Mohr rule and the second-order force based functions for computation of the generalized displacements. The proposed model allows explicit and efficient modeling of the combined effects of nonlinear geometrical effects, gradual spread-of-plasticity, partial shear connection of composite beams, finite-size joints and joint flexibility by using only one 2-noded beam-column element per physical member. For composite beams, based on elasto-plastic cross-sectional analyses the model is able to take into account the effects of partial composite action between the concrete slab and the steel beam. At the cross-sectional level the proposed method addresses computational efficiency through the use of path integral approach to numerical integration of the cross-sectional nonlinear characteristics and residual stresses, enabling in this way the accurate geometrical specifications and precise modeling of cross-sections. The proposed nonlinear analysis formulation has been implemented in a general nonlinear static purpose computer program, NEFCAD. Several computational examples are given to validate the accuracy and efficiency of the proposed method.


1992 ◽  
Vol 19 (1) ◽  
pp. 1-10 ◽  
Author(s):  
M. R. Veldanda ◽  
M. U. Hosain

This paper summarizes the results of tests performed on 48 push-out specimens to investigate the feasibility of using perfobond rib type shear connectors in composite beams with ribbed metal decks placed parallel to the steel beams. The perfobond rib shear connector is a flat steel plate containing a number of holes. The results indicate that perfobond rib connectors can be effectively used in composite beams with ribbed metal decks placed parallel to the steel beams. An appreciable improvement in performance was observed in test specimens when additional reinforcing bars were passed through the perfobond rib holes. Shank shear was the principal mode of failure in specimens with headed studs. In specimens with perfobond rib, failure was triggered by the longitudinal splitting of the concrete slab, followed by the crushing of concrete in front of the perfobond rib. Key words: composite beam, shear connector, perfobond rib, headed stud, push-out test, metal deck.


2016 ◽  
Vol 2 (2) ◽  
pp. 52-62 ◽  
Author(s):  
Hamid Eskandari ◽  
Tahereh Korouzhdeh

This study presents exact solution analysis for the cost optimization of Composite Beams (CB) based on the Load and Resistance Factor Design (LRFD) specifications. Matlab code formulation is applied to analysis of sensitivity for various parameters such as cost of concrete, steel beam, span length, concrete slab thickness, compressive strength of concrete, steel beams space and shear connectors on CB. Almost 20 thousands design were analysed to obtain various contour which be found that it is feasible, efficient and effective and capable in optimization of composite beam designs.The obtained results represent that many of the contour are capable by achieving substantial cost savings for composite materials. Therefore, the analysis can be developed for practical designs to structural designers. A parametric study was also conducted to investigate the effects of IPE, IPB, INP profiles, UNP size and thickness of slabs and beam length on the cost optimization of CB.


1986 ◽  
Vol 13 (5) ◽  
pp. 575-582 ◽  
Author(s):  
S. Elkelish ◽  
Hugh Robinson

The effective width of the concrete slab of a composite beam is used in the determination of its moment resistance and service load moment for the purposes of structural design of the composite beam. It is usually assumed that the same effective width of the concrete slab may be used for both ultimate strength and elastic stage calculations.This paper presents the results of an analytical investigation of the variation of the effective width of composite beams and ribbed slabs formed by ribbed metal deck in both the elastic and inelastic stages and at ultimate load. A layered finite element method is used to model the composite beam. The influence of four variables on the effective width of the composite beams was studied, namely, type of loading, beam span to actual concrete slab width, ultimate compressive strength of the concrete, and steel beam size.It was found that the effect of the compressive strength of the concrete and the size of the steel beam have negligible influence on the effective width of the concrete slab. The effective width of the slab at ultimate load is of the order of 4% larger than that in the elastic range.The effective width used for the design of composite beams under a uniformly distributed load, which is the practical loading in most cases, is significantly different from that which should be used for any other type of loading.


Author(s):  
Nguyen Tran Hieu

Nowadays, with the development of cutting and welding technologies, steel beams with regular circular openings, called cellular beams, have been widely used for construction. The cellular beams could be designed either as steel beam or composite beam when headed shear connectors connect concrete slab to top flange of steel beam. This paper presents a procedure to design cellular composite beams according to EN 1994-1-1. In addition, a parametric study is carried out to evaluate the influence of circular opening geometry to ultimate load and failure mode of a series of cellular composite beams. As a result, an optimal dimension of cellular beam is proposed. Article history: Received 28 February 2018, Revised 22 March 2018, Accepted 27 April 2018


1976 ◽  
Vol 3 (4) ◽  
pp. 514-522 ◽  
Author(s):  
M. N. El-Ghazzi ◽  
H. Robinson ◽  
I. A. S. Elkholy

The longitudinal shear failure of the slab of composite beams is constrained to occur at a predetermined shear surface. A method for calculating the longitudinal shear capacity of the slab of simply-supported steel–concrete composite beams is presented. The method is based on analyzing the stresses at failure of the concrete elements located at the slab shear surface.A design chart based on estimating the transverse normal stress required within the concrete slab to achieve the full ultimate flexural capacity of the composite beam is proposed. Alternatively, using elastic–plastic stress distribution across the concrete slab, the longitudinal compressive force due to bending and hence the applied moment can be predicted for any longitudinal shear capacity of the slab. The proposed design and analysis when compared to previous tests and analysis showed good agreement.The slab width and the shear span of the composite beam are found to be two important parameters which cannot be neglected when estimating the longitudinal shear capacity of the slab. These two parameters have been neglected in the empirical solutions previously adopted.


1986 ◽  
Vol 13 (1) ◽  
pp. 66-75 ◽  
Author(s):  
E. H. Fahmy ◽  
Hugh Robinson

This paper concerns the analysis and testing of 10 cantilever composite beams incorporating ribbed metal deck, representing the positive moment beam–column connections in an unbraced steel frame with composite floor beams. The positive moment beam–column connections arise from lateral forces on the unbraced frame. The effective widths of the slabs for strength and stiffness calculations have been determined from analysis. Agreement between the calculated strain distributions across the concrete slab width and the corresponding measured strain distributions was attained. Use of the calculated effective widths of the slab for strength together with a concrete strength of [Formula: see text] gave good agreement with the measured positive ultimate moment capacities of the cantilever composite beams subjected to upward end test loads.


2018 ◽  
Vol 24 (7) ◽  
pp. 95
Author(s):  
Salah R. Al-Zaidee ◽  
Ehab Ghazi Al-Hasany

This study aims to show, the strength of steel beam-concrete slab system without using shear connectors (known as a non-composite action), where the effect of the friction force between the concrete slab and the steel beam has been investigated, by using finite element simulation. The proposed finite element model has been verified based on comparison with an experimental work. Then, the model was adopted to study the system strength with a different steel beam and concrete slab profile. ABAQUS has been adopted in the preparation of all numerical models for this study. After validation of the numerical models, a parametric study was conducted, with linear and non-linear Regression analysis. An equation regarding the concrete slab-steel beam system strength in non-composite action has been pointed out. Where the actual strength of the beam without using shear connectors has been located in between the full composite action and non-composite action. However, partial-composite action has been noted, due to the effectiveness of friction force which makes the beam behave as composite before the slip occurs.  


Author(s):  
Juliano Geraldo Ribeiro Neto ◽  
Gregório Sandro Vieira ◽  
Rogers de Oliveira Zoccoli

ABSTRACT: The present work aims to compare the structural behavior of steel-concrete composite-section beams for three types of shear connectors made of U hot rolled section and cold-formed sections of U and L. Experimental tests were performed with the three types of connectors associated with I section laminated steel beams and reinforced concrete slabs. For each type of connector, three push-out tests were performed, as well as six simple supported beam tests to evaluate the positive bending moment region. The results indicated that the direct shear behavior among the different types of connectors presents significant differences, however they do not significantly influence the average flexural strength of the composite beams. These, however, present considerable differences in deflections and deformations due to the stiffness differences of the connectors.


2017 ◽  
Vol 27 (4) ◽  
pp. 143-156 ◽  
Author(s):  
Maciej Szumigała ◽  
Ewa Szumigała ◽  
Łukasz Polus

Abstract This paper presents an analysis of timber-concrete composite beams. Said composite beams consist of rectangular timber beams and concrete slabs poured into the steel sheeting. The concrete slab is connected with the timber beam using special shear connectors. The authors of this article are trying to patent these connectors. The article contains results from a numerical analysis. It is demonstrated that the type of steel sheeting used as a lost formwork has an influence on the load-bearing capacity and stiffness of the timber-concrete composite beams.


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