scholarly journals Behavior of Curved Steel-Concrete Composite Beams Under Monotonic Load

Author(s):  
Abdulkhaliq A. Jaafer ◽  
Saba L. Kareem

The paper develops a numerical investigation on the behavior of steel-concrete composite beam curved in plan to examine the effect of the various parameters. Three-dimensional finite element analysis (FEA) is employed using a commercial software, ABAQUS. The geometric and material nonlinearities are utilized to simulate the composite beam under a monotonic load. The FEA efficiency has been proved by comparing the numerical results with experimental tests obtained from previous literature, including load-deflection curves, ultimate load, ultimate and failure deflection, and cracks propagation. The validated models are used to assess some of the key parameters such the beam span/radius ratio, web stiffeners, partial interaction, concrete compressive strength, and steel beam yield stress. From the obtained results, it is noticed that the span/radius of curvature ratio influences the loading capacity, the beam yielding (i.e. the beam yield at an early stage) when the span/radius ratio increases and inelastic behavior developed early of the beam due to the torsional effect. The presence of web stiffeners with different locations in the curve composite beam affected the shear strength. The web twisting and vertical separation at the beam mid-span are observed to decrease as the number of the stiffeners increase due to the decrease in the beam torsion incorporating with transferring the failure to the concrete slab. Furthermore, the partial interaction and steel beam yield stress developed in this study appear to have a remarkable effect on beam capacity.

2018 ◽  
Vol 11 (4) ◽  
pp. 757-778
Author(s):  
A. R. SILVA ◽  
L. E. S. DIAS

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.


2011 ◽  
Vol 33 (1) ◽  
pp. 13-26
Author(s):  
Le Luong Bao Nghi ◽  
Bui Cong Thanh

This paper presents a displacement-based finite element formulation for nonlinear analysis of steel - concrete composite planar frames subjected to combined action of gravity and lateral loads. A 6DOF super element is proposed for modeling composite beam, allowing for partial interaction between the steel beam and the concrete slab, semi-rigid nature of beam to column composite connection and material nonlinearity. The load control method and the displacement control method are utilized for tracing the structural equilibrium paths, and the direct method is utilized for solving the nonlinear problem. Numerical examples, concerning a two-span continuous composite beam, a portal composite frame and a six-storey composite frame, are performed. The results are compared with experience data or theoretical results from other studies and are discussed for influences of the factors mentioned above on behaviour of composite beams and composite frames.


2013 ◽  
Vol 663 ◽  
pp. 149-153
Author(s):  
Seung Hun Kim ◽  
Soo Yeon Seo ◽  
Chang Geun Cho

In the newly developed excavation system for construction of basement of building, steel elements plays a role as temporary member before casting floor concrete, but it do behavior as composite beam mixed with concrete after floor slab has been casted. That is, it is necessary to review if axial stress loaded in steel beam can be conveyed properly to slab, as casting concrete slab under conditions of application of compression to the steel beam In this manner, this paper presents the experimental result of the composite beam subjected to both constant axial load and variable vertical load. Main parameters in the test are magnitude and loading time of axial force. As a result, it was found that there was no effect on the flexural strength according to the timing of compression and axial force. The flexural strength of the composite beam subjected to both a constant axial compression and increasing vertical load could be predicted with somewhat safety by using code equations.


2019 ◽  
Vol 9 (1) ◽  
pp. 207 ◽  
Author(s):  
Xinggui Zeng ◽  
Shao-Fei Jiang ◽  
Donghua Zhou

In a steel-concrete composite beam (hereafter referred to as a composite beam), partial interaction between the concrete slab and the steel beam results in an appreciable increase in the beam deflections relative to full interaction behavior. Moreover, the distribution type of the shear connectors has a great impact on the degree of the composite action between the two components of the beam. To reveal the effect of shear connector layout in the performance of composite beams, on the basis of a developed one-dimensional composite beam element validated by the closed-form precision solutions and experimental results, this paper optimizes the layout of shear connectors in composite beams with partial interaction by adopting a stepwise uniform distribution of shear connectors to approximate the triangular distribution of the shear connector density without increasing the total number of shear connectors. Based on a comparison of all the different types of stepped rectangles distribution, this paper finally suggests the 3-stepped rectangles distribution of shear connectors as a reasonable and applicable optimal method.


2018 ◽  
Vol 203 ◽  
pp. 06010
Author(s):  
Nadiah Loqman ◽  
Nor Azizi Safiee ◽  
Nabilah Abu Bakar ◽  
Noor Azline Mohd Nasir

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.


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.


2011 ◽  
Vol 243-249 ◽  
pp. 1072-1084 ◽  
Author(s):  
Qiong Yu ◽  
Zhou Dao Lu ◽  
Jiang Tao Yu ◽  
Xing Zhuang Zhao ◽  
Jin Dai

Test of two specimens (four different joints) of steel secondary beam embedded in reinforced concrete girder in frame structure and one specimen with steel cantilever beam embedded in reinforced concrete girder under static load were conducted. The steel beam up-flange was pulled out because of the concrete cracks caused by the moment, shear and torsion at the upper zone of the concrete beam near the steel beam end. Shear failure of the concrete beam and the top flange pullout failure are the most hazardous failure modes. Lacking restraint of concrete and the reinforcement of steel bar in the concrete slab and catenary action of restraint steel beam, the capacity of steel cantilever beam is much smaller than other beams. Load-slip curve of top flange of steel beam, load-rotation curve of the steel beam end are obtained through experiment. Primary calculation method of joints flexural capacity related to section size of composite steel beam, embedded depth of steel beam, flange width of steel beam embedded end, height of frame girder, is put up with. Analytical results of ABAQUS are shown as follows. Top flange pullout failure of steel beam is caused by the detachment of concrete and steel beam end, and the warp of the concrete slab near the support plays an unfavorable action on the performance of the steel beam. The end rotational angle of the steel beam with anchor bar is smaller than that without. The steel beam with shear connectors develops a smaller rotational angle and a higher load capacity.


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.


2018 ◽  
Author(s):  
◽  
Ayman Elzohairy

[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.


Sign in / Sign up

Export Citation Format

Share Document