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

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%.

2016 ◽  
Vol 123 ◽  
pp. 79-92 ◽  
Author(s):  
Ying Xing ◽  
Qinghua Han ◽  
Jie Xu ◽  
Qi Guo ◽  
Yihong Wang

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.


2014 ◽  
Vol 578-579 ◽  
pp. 184-187
Author(s):  
Xu Dong Wang ◽  
Li Zhu ◽  
Pei Jun Wang

The fire design of structural members depends on its temperature distributions. This paper investigates the temperature distributions of protected cellular composite beams heated three sides. Modeling in ABAQUS indicates that the fire protection and the concrete slab make a big difference to the temperature distributions of steel beams. Temperature gradient exists across the web region of the steel beam. Comparison with predictions from European design codes shows a good correlation between each other, but some discrepancies exist for the top flange.


1983 ◽  
Vol 10 (4) ◽  
pp. 713-721 ◽  
Author(s):  
R. G. Redwood ◽  
G. Poumbouras

Tests of composite beams comprising a concrete slab supported on a steel deck and a steel wide-flange shape containing large web openings are described. Special attention is directed to the amount of shear connection between slab and steel section in the region of a web hole, and on the effect of construction loads acting on the steel section prior to composite action being effective.It is shown that limited shear connection at the hole will significantly affect the strength when loading produces a high shear-to-moment ratio, and a theory is presented which conservatively takes this into account. The effect of construction loads on unshored construction is shown to be small when these do not exceed 60% of the non-composite beam resistance at the hole.


2019 ◽  
Vol 12 (3) ◽  
pp. 509-517
Author(s):  
O. P. AGUIAR ◽  
R. B. CALDAS ◽  
F. C. RODRIGUES ◽  
H. N .BELLEI

Abstract In search of an improved compatibility between cold-formed steel profiles and precast floor systems, this study proposes an alternative shear connector for cold-formed steel-concrete composite beams. This connector consists of a steel plate with holes placed longitudinally in the middle of the upper flange of the steel profile, aiming to maximize the support area for precast slabs during the assembly. The proposed solution was experimentally tested on I-beams under bending, composed by two cold-formed steel channels, connected to a reinforced concrete slab by the shear connector. The relative slip between the steel profile and concrete, vertical deflection of the beam, and strains at several locations of the composite section were measured. The results show that the proposed connector assures shear transfer at the interface of the composite section components and shows strength of the same magnitude as other commonly used connectors.


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.


2014 ◽  
Vol 1044-1045 ◽  
pp. 71-74
Author(s):  
Jing Ping Yang

In order to investigate mechanics performance of rubber concrete steel composite beam, nonlinear analysis on four steel concrete composite beams with different amount of rubber has been carried out using finite element analysis software, and the influence of rubber concrete to mechanical properties of composite beam was explored. The results show that ductility, crack resistance of rubber concrete slab, shear capacity of shear connector for rubber concrete steel composite beam are improved significantly compared with ordinary steel concrete composite beams. Along with the increase of rubber content, the energy consumption of composite beams gradually increases, while the ultimate bearing capacity decreases with small amplitude. As a kind of green environmental protection material Rubber Aggregate concrete has the characteristics of good ductility, crack resistance is strong, energy consumption is obvious and good wear resistance.


Author(s):  
Gustavo Coldebella ◽  
Sineval Esteves Pereira Junior ◽  
Silvana De Nardin

Abstract Steel-concrete slim flooring system using precast concrete hollow core slabs and steel beam with web openings is an innovative construction system designed to combine the high bending resistance of both precast prestressed hollow core slabs and steel beam with web openings. This system can provide floor systems with a minimum constructional depth in comparison with ordinary composite floors. The aim of this study was to evaluate in an exploratory way the shear transferring mechanism between the steel beam with circular web opening and the precast hollow-concrete slab. The shear connection is formed by in-situ concrete passes through the web openings and infill the voids of the precast slabs. One push-out test was conducted to investigate the shear transferring mechanism of shear connection and the experimental results were compared to analytical methods. The shear resistance of the shear connection was predicted with good accurate by analytical methods.


2013 ◽  
Vol 351-352 ◽  
pp. 427-433 ◽  
Author(s):  
S.O. Bamaga ◽  
M.Md. Tahir

Introducing low cost housing is one of the challenges face civil engineers now-days. Using lightweight construction materials i.e. cold formed steel sections is an alternate solution to overcome the challenge. In this study, a lightweight composite beam was introduced. It consists of cold formed steel section and profiled concrete slab. Experimental push tests were conducted to investigate the ductility and strength capacities of new and innovative shear connectors. The shear connectors were easy to form and give advantages to speed up the fabrication process of the proposed composite beam. The shear connectors showed large deformation and strength capacities. It is concluded that the proposed shear connectors could be used for lightweight composite beams.


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