Effective widths of composite beams with ribbed metal deck

1986 ◽  
Vol 13 (5) ◽  
pp. 575-582 ◽  
Author(s):  
S. Elkelish ◽  
Hugh Robinson
Keyword(s):  
Compressive Strength ◽  
Composite Beam ◽  
Ultimate Load ◽  
Concrete Slab ◽  
Composite Beams ◽  
Analytical Investigation ◽  
Steel Beam ◽  
Effective Width ◽  
Slab Width ◽  
Service Load

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.

scholarly journals Numerical analysis of the effect of partial interaction in the evaluation of the effective width of composite beams

2018 ◽  
Vol 11 (4) ◽  
pp. 757-778
Author(s):  
A. R. SILVA ◽  
L. E. S. DIAS
Keyword(s):  
Composite Beam ◽  
Concrete Slab ◽  
Composite Beams ◽  
Interface Element ◽  
Steel Beam ◽  
Real Problem ◽  
Effective Width ◽  
Plate Element ◽  
Technical Standards ◽  
Partial Interaction

Abstract Most of the engineering problems involving structural elements of steel-concrete composite beam type are approximations of the structural problem involving concrete plates connected by connectors to steel beams. Technical standards allow the replacement of the concrete plate element by a beam element by adopting a reduction in the width of the plate element known as effective width. The effective width is obtained, in most technical norms, taking into account only the parameters of beam span length and distance between adjacent beams. Numerical and experimental works found in the literature show that this effective width depends on several other parameters, such as the width and thickness of the concrete slab, and the type of loading. The objective of this work is to verify the influence of the partial interaction in the evaluation of the effective width of composite beams formed by a concrete slab connected to a steel beam with deformable connection, being used in numerical simulation three types of finite elements: a plate element for nonlinear analysis of the concrete slab; a bar element for non-linear analysis of beams with cross-section defined by a polygon; and an interface element which connects the plate and beam elements, simulating the deformation effect of the shear connectors. In the studied examples, it was found that the reduction of the shear connection stiffness at the interface between the concrete slab and the steel beam leads to a decrease in the shear lag effect and, consequently, makes the effective width of the concrete slab closer to the its real width. In another example, curves are constructed to define the effective width of a composite beam with medium stiffness. Considering maximum stresses and maximum displacements, these curves are obtained by forcing the equivalence of the approximate model with the model closest to the real problem.

scholarly journals Longitudinal shear capacity of the slabs of composite beams

1976 ◽  
Vol 3 (4) ◽  
pp. 514-522 ◽  
Author(s):  
M. N. El-Ghazzi ◽  
H. Robinson ◽  
I. A. S. Elkholy
Keyword(s):  
Composite Beam ◽  
Shear Failure ◽  
Concrete Slab ◽  
Compressive Force ◽  
Longitudinal Shear ◽  
Composite Beams ◽  
Shear Capacity ◽  
Slab Width ◽  
Two Parameters ◽  
Concrete Elements

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.

scholarly journals Effective Flange Width for Composite Steel Beams

2011 ◽  
Vol 7 (2) ◽  
pp. 28 ◽  
Author(s):  
T. Salama ◽  
H.H. Nassif
Keyword(s):  
Concrete Slab ◽  
Composite Beams ◽  
Analytical Investigation ◽  
Steel Beams ◽  
Limit States ◽  
Composite Action ◽  
Shear Connectors ◽  
Slab Width ◽  
Effective Flange Width ◽  
Composite Steel

 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. 

scholarly journals Structural Behavior of Steel-Concrete Composite Beam using Bolted Shear Connectors: A Review

2018 ◽  
Vol 203 ◽  
pp. 06010
Author(s):  
Nadiah Loqman ◽  
Nor Azizi Safiee ◽  
Nabilah Abu Bakar ◽  
Noor Azline Mohd Nasir
Keyword(s):  
Composite Beam ◽  
Concrete Slab ◽  
Precast Concrete ◽  
Composite Beams ◽  
Reinforced Concrete Beams ◽  
Structural Behavior ◽  
Concrete Slabs ◽  
Steel Beam ◽  
Shear Connectors ◽  
Beam System

Conventional steel-concrete composite beams have been recognized to exhibit stronger structural characteristics, in terms of strength and stiffness, when compared to pure steel or reinforced concrete beams. However, currently most steel beam is fully attached to the concrete slab; this means that the shear connectors are welded through the steel decking on to the steel beam and cast into concrete slab to fulfill the necessary shear connection. Recently, the deconstruction and reuse of the components almost impossible. In order to achieve a sustainable structural system, precast concrete slabs are attached to a steel beam using bolted shear connectors in prefabricated holes have been introduced as an alternative to the conventional connectors in steel – concrete composite beam system. This paper reviews the structural behavior of composite beam system such as the strength, stiffness, slip behavior, failure mode and sustainability obtained by experiment and numerical studies in order to address the applicability and efficiency of the composite beams having precast concrete slabs and bolted shear connectors.

scholarly journals Simplified design method and parametric study of composite cellular beam

2018 ◽  
Vol 12 (3) ◽  
pp. 34-43
Author(s):  
Nguyen Tran Hieu
Keyword(s):  
Parametric Study ◽  
Ultimate Load ◽  
Design Method ◽  
Concrete Slab ◽  
Composite Beams ◽  
Steel Beams ◽  
Steel Beam ◽  
Optimal Dimension ◽  
Shear Connectors ◽  
Cellular Composite

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

Monotonic and fatigue assessment of steel-concrete composite beams strengthened with externally post-tensioned tendons

2018 ◽  
Author(s):  
◽  
Ayman Elzohairy
Keyword(s):  
Numerical Model ◽  
Composite Beam ◽  
Composite Beams ◽  
Fatigue Tests ◽  
Flexural Behavior ◽  
Bending Test ◽  
Steel Beam ◽  
Premature Failure ◽  
Post Tensioning ◽  
Post Tensioned

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] The steel-concrete composite beam represents a structural system widely employed in both buildings and girder bridges. The coupling between steel beams and concrete flanges assures both economic and structural benefits because of quick construction of steel structures and large increase in stiffness due to the presence of concrete. Strengthening with external post-tensioning (PT) force is particularly effective and economical for long-span steel-concrete composite beams and has been employed with great success to increase the bending and shear resistance and correct excessive deflections. Applying external PT force to the steel-concrete composite beam is considered an active strengthening technique that can create permanent internal straining action in the beam which is opposite to the existing straining action due to the applied service loads. The most benefits of using this system of strengthening are an elastic performance to higher loads, higher ultimate capacity, and reduction in deformation under the applied loads. Under service loads, bridge superstructures are subjected to cyclic loads which may cause a premature failure due to fatigue. Therefore, fatigue testing is critical to evaluate existing design methods of steel-concrete composite beams. ... This research presents static and fatigue tests on four steel-concrete composite specimens to evaluate the effect of externally post-tensioned tendons on the ultimate strength and fatigue behavior of composite beams. Fatigue tests are conducted to a million cycles under a four-point bending test. In addition, final static tests are performed on fatigued specimens to evaluate the residual strength of the strengthened specimen. A numerical model is described to predict the fatigue response of the composite beam by considering the fatigue damage in the concrete flange. The accuracy of the developed numerical model is validated using the existing test data. The static test results indicate that the external post-tensioning force improves the flexural behavior of the strengthened specimen by increasing the beam capacity and reducing the tensile stress in the bottom flange of the steel beam. The fatigue results demonstrate that the external post-tensioning significantly decreases the strains in the shear connectors, concrete flange, and steel beam. The tendons demonstrated an excellent fatigue performance, with no indication of distress at the anchors.

Analyses and tests to determine the effective widths of composite beams in unbraced multistorey frames

1986 ◽  
Vol 13 (1) ◽  
pp. 66-75 ◽  
Author(s):  
E. H. Fahmy ◽  
Hugh Robinson
Keyword(s):  
Concrete Slab ◽  
Concrete Strength ◽  
Composite Beams ◽  
Steel Frame ◽  
Slab Width ◽  
Lateral Forces ◽  
Measured Strain ◽  
Ultimate Moment ◽  
Strength And Stiffness ◽  
Good Agreement

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.

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.

scholarly journals Numerical Modelling Of The Strengthening Process Of Steel-Concrete Composite Beams

2015 ◽  
Vol 19 (4) ◽  
pp. 99-110 ◽  
Author(s):  
Piotr Szewczyk ◽  
Maciej Szumigała
Keyword(s):  
Numerical Modelling ◽  
Bearing Capacity ◽  
Composite Beam ◽  
Steel Plate ◽  
Composite Beams ◽  
Steel Beam ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Main Assumption ◽  
The Cost

Abstract This paper presents the numerical modelling of strengthening a steel-concrete composite beam. The main assumption is that the strengthening is not the effect of the state of a failure of a structure, but it resulted from the need to increase the load-bearing capacity and stiffness of the structure (for example: due to a change in the use of the object). The expected solution is strengthening without the necessity to completely unload the structures (to reduce the scope of works, the cost of modernization and to shorten the time). The problem is presented on the example of a composite beam which was strengthened through welding a steel plate to the lower flange of the steel beam. The paper describes how energy parameters are used to evaluate the efficiency of structures’ strengthening and proposes an appropriate solution.

scholarly journals Strengthening of Composite Steel-Concrete Beams Openings by Adopting Different Reinforcement Methods

2019 ◽  
pp. 1-17
Author(s):  
Mohamed H. Makhlouf ◽  
Hala M. Refat
Keyword(s):  
Numerical Study ◽  
Concrete Slab ◽  
Low Cost ◽  
Composite Beams ◽  
Experimental Program ◽  
Bottom Surface ◽  
Steel Beam ◽  
Web Openings ◽  
Line Load ◽  
Steel Composite

This paper presents an experimental and numerical study carried out to investigate the flexural and shear behavior of concrete-steel composite beams with circular web openings strengthened using two different techniques around openings. The experimental program conducted on nine simply supported beams which were constructed with different variables. One steel beam and eight concrete-steel composite beams were experimentally tested. The tested beams are of 1500 mm length and BFI cross section of steel beam but composite beams were BFI steel section connected with concrete slab had 300 mm width and 70 mm depth, while this connection is done by headed stud shear connector. The tested specimens subjected to positive bending were loaded by one or two line load across the width of the concrete slab. The main parameters were the type of beams, web openings effect, location of web openings, strengthening techniques around openings externally CFRP strips and vertical steel links using steel plates placed on the top and bottom surface of beams anchored with fine threads, and number of CFRP strips layers. The effect of these parameters on the failure of modes, ultimate load, first cracking load and deflection were investigated. Moreover, a finite element models were developed by ANSYS (version 14) to simulate all the tested specimens, experimental test results were compared with FE results obtained. The experimental results showed that both strengthening systems applied in this research were remarkably increased the beam strength, and the capacity retrieve of beams without openings. This study approved that steel links technique gave more prominent simplicity of use and low cost. FEM models were in good agreement with the corresponding experimental ones. However, the calculated ultimate loads were slightly higher than the experimental ultimate loads up to 10%.

Sign in / Sign up

Export Citation Format

Share Document