Behavior Of Steel-concrete Composite Beams Research Articles

Experimental study on the effect of partial shear studs layout on flexural behavior of steel-concrete composite beams

In steel-concrete composite beams, partial shear connection offers advantages including greater ductility and lower cost. However, partial shear connection constraints on composite beam structural performance, such as reduced beam stiffness, increased steel-concrete interface slip, etc., should not be neglected. Several researches have revealed that shear connector layout is one of the main approaches to limit partially composite beam vulnerability. Shear connector layout optimization has not been completely investigated experimentally, and its effect on composite beam structural performance is still unknown. This paper focusses on the experimental study of the effect of shear connectors layout on the flexural performance of composite beams. It reports the optimization of the layout of shear connectors based on blocked distribution of shear connectors laid in a single row, while concentrating the highest number of shear studs towards the supports of a simply supported composite beam. A fully composite beam with normal layout of shear studs was tested as control specimen, while the rest of the beams used partial shear connection (η = 0.5). Beams with partial shear connection had 3 different layouts of shear studs. The first had uniformly distributed shear studs, and the rest had shear studs laid out in 2 and 3 blocks each of uniform spacing respectively. The results showed that the beam with 3 blocks layout each of equal spacing of shear studs had the closest best structural performance to the fully composite beam and had better ductility than the latter.

Experiment study on flexural performance of steel concrete composite beams under salt freeze-thaw cycles in negative moment sections

Bridge structures in cold climates face significant challenges due to freeze-thaw cycles and salt-induced corrosion. This study investigates the degradation mechanisms of the negative bending behavior of steel-concrete composite beams using normal concrete (NC) and ultra-high performance concrete (UHPC) under salt freeze-thaw cycles (SFTC), considering the impact of different stud arrangements. The results indicate that UHPC significantly enhances the cracking performance in the negative bending region of the composite beams and demonstrates high resistance to SFTC. Before undergoing SFTC, the cracking moment of the UHPC beams increased by an average of 210.5%, and stiffness by 37.3%, compared to the NC composite beams. After 150 SFTCs, the NC beams showed a significant decline in performance, with a 62.1% reduction in cracking moment, a 6.2% decrease in load-carrying capacity, and a 5.6% reduction in stiffness. In contrast, the flexural performance of the UHPC beams was almost unaffected, with only a 17.5% reduction in cracking load. Moreover, beams with a double-row stud configuration exhibited better negative bending resistance compared to those with a single-row stud configuration. Based on experimental results and data from reference, a reasonable formula for predicting the composite beams under the effect of SFTCs was proposed and proved to have satisfactory accuracy.

Analysis of Stud Spacing on the Mechanical Behaviour of Steel-Concrete Composite Beam under Uniform Load

The stud spacing significantly affects the bond strength and interracial slip between steel and concrete of thin-walled steel-concrete composite beams, and it interacts with shear lag and shear deformation to affect the structural deflection and sectional stresses. In this paper, a new interracial slip model considering the influence of stud spacing and stud shear stiffness is proposed first, then a potential energy equation of a simply supported steel-concrete composite beam under vertical uniform load considering the coupled effect of interracial slip, shear lag and shear deformation is obtained, and the calculation formulae for structural deflections and sectional stresses are derived, in which the parameter of stud spacing is explicitly shown. The comparison between the observed data in the completed experiment with the theoretical values using the presented formulae and the design code formulae are fulfilled, showing that the presented formulae hold agreeable calculation precise. The proposed formulae can be used to estimate the influence of stud spacing on the mechanical behaviour of steel-concrete composite beams in the preliminary design.

Numerical study of steel–concrete composite beams strengthened by CFRP plates with prestressed unbonded reinforcement system

This work developed a three-dimension refined finite element (FE) model to study the flexural behavior of steel–concrete composite beams strengthened with CFRP plate by prestressed unbonded reinforcement (PUR) system. The numerical result has excellent agreements with the experimental results on the failure mode, overall load–deflection response and strain development at mid-span section as well as CFRP plates. The verified FE model was applied to carry out a comprehensive parametric study, evaluating the effects of sectional area, prestress level and profile of CFRP plate, to investigate the optimum parameter range of PUR system for beam reinforcement. It is found that the yielding load rises as the sectional area, prestress level, and pillar spacing of CFRP plates increase. Besides, the ultimate bearing capacity of beam can be efficiently improved by increasing the sectional area of CFRP plates, while the mid-span deflection and ductility were maintained at failure. Moreover, as the prestress level of CFFR plate increases, the bearing capacities of reinforced beams marginally rise but the ductility markedly decreases. The ideal prestress level for strengthening is considered as 10 %∼30 %. Furthermore, the profile of CFRP plate has significant impact on failure of reinforced beams, but has little effect on ultimate load. The results of parametric studies are of great significance for the practical reinforcement application of the PUR system with CFRP in bridge engineering.

Investigation on permanent deformation in steel-concrete composite beam bridge deck pavement under temperature-load coupling effect

Rutting is one of the common distresses observed in asphalt pavement, influenced by temperature and load conditions. To clarify the permanent deformation behavior of steel-concrete composite beam (SCCB) bridge deck pavement under temperature-load coupling effect and provide references for the distress cause analysis, five typical SCCB bridge deck pavements were selected. The temperature distribution and the temperature stress of the pavement structures were analyzed by numerical simulation under periodic temperature variations. In addition, considering the daily variation in traffic volume, the permanent deformation of the five pavement structures were calculated under temperature-load coupling effect. Finally, the influence of heavy load on the development of rutting distress was also investigated. The results show that the temperature field and temperature stresses within the SCCB bridge deck pavement exhibit periodic variations under periodic temperature variations. Additionally, after 500,000 times of standard axle load application, “EA + SMA” exhibits the smallest permanent deformation and the best resistance to rutting distress under temperature-load coupling effect. Finally, heavy load conditions have a great influence on the permanent deformation of SCCB bridge deck pavement. In areas with severe rutting distresses, it is recommended to use “EA + SMA” pavement structure in SCCB bridge.

Three-Dimensional Numerical Simulation for Lateral Distortional Buckling Behaviour of Steel-Concrete Composite Beams

Lateral Distortional Buckling (LDB) is a mode of instability in Steel-Concrete Composite (SCC) beams that is yet to be fully understood by the structural engineering research and design community. This work investigated numerical methods to understand the LDB behavior of SCC beams under negative moments that exhibit nonlinear behavior. Focus of the study was to develop and validate 3-Dimensional finite element (FE) models which capture the LDB behavior of SCC beams precisely. Detailed 3-Dimensional FE models of the SCC beams were developed using ABAQUS. For modeling concrete, a nonlinear damage plasticity model was considered. A quad-linear curve was used to describe the stress-stain relationship for the steel beam. The stress-stain relationship for the rebar was described using a bi-linear curve while an elastic perfectly plastic model was assigned to the headed stud shear connectors. Steel hardening behavior was simulated using an isotropic hardening model. The interaction between the concrete slab, steel beam, and studs was described using appropriate interface elements combined under suitable constraints. The FE model’s accuracy was validated by results obtained from previous experiments found in literature together with a brief description of the experiments done by previous researchers to ensure completeness. Validation of the model was done by comparing Moment-Rotation curves obtained from the experimental tests, lateral displacements of the bottom flange along the axial direction and comparison of the failure modes between the numerical model and experimental test specimens. It was observed that the maximum relative error for the ultimate moment capacity of the composite beams from FE analysis and the experimental tests was less than 2% which shows that the FE model was in strong agreement with the experimental results. Accordingly, the numerical model developed herein proves to be capable of accurately representing the LDB phenomenon.

Performance of steel-concrete composite beams

ABSTRACT Steel-concrete composite construction picked up its utility because of efficient combination of steel and concrete offering high ductility, strength and stiffness to the structure. Loading action is one of the key parameters to understand the behaviour of a structural element. An attempt has been made in this paper to review the structural performance of steel-concrete composite beams under different loading actions. In addition, the results of nonlinear analysis of steel-concrete composite beams subjected to static loading, using commercial finite element software ANSYS, have been included. Numerical investigations have been performed to understand the behaviour of steel-concrete composite beams under static loading criteria. Numerical models of beams have been created and two-point loading was applied. Load versus mid-span deflection has been plotted. Earlier, validation has been done by comparing the analysis results by authors with the experimental results obtained by previous authors available in literature. The results obtained have shown that dimensions of shear connectors used are having influence on ultimate load capacity of steel-concrete composite beams subjected to static loading.

Nonlinear analysis of steel-concrete composite beams with flexible shear connectors

Steel-concrete composite beam is a typical construction which is made up of two dissimilar materials such as steel and concrete. It is used mainly for construction of commercial/residential high-rise buildings and bridges. From last few decades steel-concrete composite structure has been utilised in construction industry due to several advantages such as reduced time and cost of major construction and the avoidance of one of the major issues in present era, space scarcity. Shear connector is a basic component through which steel and concrete components are mechanically connected to transfer the load from concrete slab to steel beam in a conventional type of steel-concrete composite beam. Three dimensional numerical models are created using finite element analysis commercial software package ANSYS15 to study the flexural capacity of beam specimens. Earlier, validation has been done with the test results available in the literature and the proposed model is found to be capable of analysing the specimens with acceptable accuracy. Further numerical models are made to understand the behaviour of steel-concrete composite beam which is made up of two different flexible shear connectors such as stud and channel connector under four-point bending. Degree of shear connection, geometry and layout of shear connectors are taken into account as key parameters for this present numerical study. Normal strength of concrete is considered. The associated results such as ultimate load, mid-span deformation, interfacial slip capacity are presented. Diameter along with length of stud connector is found to influence the load carrying capacity of beams. Ultimate load capacity as well as stiffness of beams is found to enhance when channel section is considered with minimal spacing of connector. Thus finding the required degree of shear connection was also proved to be vital for assessing the performance of steel-concrete composite beams.

Numerical investigation of steel-concrete composite (SCC) beam subjected to combined blast-impact loading

Existing literatures on combined effects of blast-impact loadings on steel-concrete composite beams are limited. In this study, behavior of steel-concrete composite beam subjected to combined blast-impact loading was investigated using LS-DYNA nonlinear FEA software program. The accuracy and reliability of developed FEA model was validated using experimental data reported in literature. Parametric studies were performed on impacting speed, concrete strength, various characteristics of H-structural steel, yield strength of studs and steel rebars to get insight into performance of composite beam subjected to combined blast impact loading. FEA results revealed that increase in specified cylindrical compressive strength of concrete, yield stress, flange and web thicknesses of H-type structural steel beam significantly improved dynamic response of a steel-concrete composite beam under combined impact-blast load case whereas yield stress of studs, and reinforcement steel bars showed insignificant contribution. Moreover, increasing impactor’s initial velocity significantly affects dynamic response of a SCC beam under combined blast-impact loading.

Study on the Flexural Behavior of Steel-Concrete Composite Beams Based on the Shear Performance of Headed Stud Connectors

Headed studs have been widely used as shear connectors in steel-concrete composite beams for a long time. Studies on the influence of the different shear properties of headed studs on the flexural behavior of the composite beams have been inconclusive. In this research, we studied the shear performance influence of headed studs by conducting static push-out tests on seven designed push-out specimens. The flexural behavior of a steel-concrete composite beam connected by studs was discussed in detail by conducting a two-point symmetric monotonic static loading test. Based on the actual situation of the composite beam test, a finite element numerical model was established and validated, in which the elastic connections units were used to simulate the studs, and the force–slip data obtained from the push-out tests were used as the constitutive model of the studs. The effects of the stud diameter, stud height, the number of studs arranged, and concrete strength on the flexural behavior of the composite beams were analyzed and compared. The results showed that the number of studs arranged had a significant influence on the flexural behavior of the composite beams, followed by the strength of the concrete. The specifications of the studs had little effect on the flexural behavior of the composite beams within the study scope using the modeling method in this paper.

Numerical investigation of steel-concrete composite beams using flexible shear connectors

<abstract> <p>This paper focuses on the investigation of the flexural behaviour of steel-concrete composite beams through non-linear finite element analysis. Both geometries, as well as material non-linearity, are considered. Steel-concrete composite beams are typically made consisting of a hot-rolled I-section steel beam and a concrete slab that is connected monolithically by using a shear connector. A shear connector is one of the key elements for developing the composite action used in steel-concrete composite structures. This paper deals with the flexible shear connectors such as studs and channels designed as per the Indian standards 11384. Initially, the FE models are validated by making comparisons with the experimental test results obtained by previous researchers, as available in the literature. In the present study, thirty three-dimensional simply supported composite beams are created and analysed using finite element commercial software package ANSYS15 workbench version subjected to two-point loads. The degree of shear connection, the strength of steel section and the geometry of stud and channel connectors are the primary parameters considered for the present research work, and the results are compared. The overall flexural response is provided, including failure modes, load-central deformation behaviour, and interface slip, as well as the effects of yield strength of steel, the geometry of the stud and channel shear connector along with the degree of shear interaction, are evaluated. The results show that the degree of interaction, the geometry of shear connectors and steel yield strength have significant influence. Subjected to flexure, steel-concrete composite beam section with channel connector is less evaluated so far; therefore, in the present research work, channel shear connector is taken into account to evaluate the flexural behaviour with the consideration of varying grades of steel section along with the degree of interaction and to compare the results with a different section of shear connectors.</p> </abstract>

Monotonic and fatigue behavior of steel-concrete composite beams subjected to corrosion

Steel-concrete composite structures are widely adopted in civil engineering attributed to the large span-to-depth ratio, light weight and rapid construction. However, long-term behavior of these structures attacked by environmental agents has not been fully investigated. This study presents an experimental study on monotonic and fatigue behavior of steel-concrete composite beams subjected to corrosion. Ten specimens were prepared using accelerated artificial corrosion and tested under four-point bending with a special focus on the effect of corroded studs. Different failure modes were observed for the specimens tested by static and fatigue loading. Corrosion was demonstrated detrimental effect on both monotonic load-bearing capacity and fatigue life of the specimens. The residual bending stiffness also decreased with corrosion rates.

Steel-Concrete Composite Beams with Precast Hollow-Core Slabs: A Sustainable Solution

Industrialization of construction makes building operation more environmental friendly and sustainable. This change is necessary as it is an industry that demands large consumption of water and energy, as well as being responsible for the disposal of a high volume of waste. However, the transformation of the construction sector is a big challenge worldwide. It is also well known that the largest proportion of the material used in multistory buildings, and thus its carbon impact, is attributed to their slabs being the main contributor of weight. Steel-Concrete composite beams with precast hollow-core slabs (PCHCSs) were developed due to their technical and economic benefits, owing to their high strength and concrete self-weight reduction, making this system economical and with lower environmental footprint, thus reducing carbon emissions. Significant research has been carried out on deep hollow-core slabs due to the need to overcome larger spans that resist high loads. The publication SCI P401, in accordance with Eurocode 4, is however limited to hollow-core slabs with depths from 150 to 250 mm, with or without a concrete topping. This paper aims to investigate hollow-core slabs with a concrete topping to understand their effect on the flexural behavior of Steel-Concrete composite beams, considering the hollow-core-slab depth is greater than the SCI P401 recommendation. Consequently, 150 mm and 265 mm hollow-core units with a concrete topping were considered to assess the increase of the hollow core unit depth. A comprehensive computational parametric study was conducted by varying the in situ infill concrete strength, the transverse reinforcement rate, the shear connector spacing, and the cross-section of steel. Both full and partial interaction models were examined, and in some cases similar resistances were obtained, meaning that the same strength can be obtained for a smaller number of shear studs, i.e., less energy consumption, thus a reduction in the embodied energy. The calculation procedure, according to Eurocode 4 was in favor of safety for the partial-interaction hypothesis.

Experimental study on mechanical behavior of steel-concrete composite beams with friction connections in different structural zones

in order to study the mechanical properties of steel-concrete composite beams with asymmetric friction connections and considering the structural factors, three simple steel-concrete composite beams with friction connections were fabricated, and the uniaxial low cycle cyclic loading sine wave tests were carried out on the steel-concrete composite beams with friction connections. The test results show that the composite beam can get stable two-stage hysteretic curve in structure 1 and structure 3, and has reliable hysteretic energy dissipation capacity. The hysteretic curve of structure 1 is more full and stable, and the strength increases first and then decreases with the loading.

Finite Element Modeling of Steel-concrete Composite Beams with Different Shear Connection Degrees

In order to study the behavior of Steel-concrete composite beams with different shear connection degrees, using finite element software ABAQUS, four models with different numbers of headed studs are established, all of which apply appropriate concrete and steel constitutive models, and contact relationship. The accuracy of finite element models is verified by comparing the simulation results with corresponding beam tests in multiple aspects, for instance, the interface slip, the ultimate capacity, the failure modes and the load-strain distribution. The analysis focuses on the interface slip development of composite beams with different connection degrees, and the results show that the interface slip seldom becomes the control condition when designing composite beams. A further parametric study is performed to investigate the effect of various parameters on the static response of composite beams. Finally, the applicable conditions and limitations of different modeling methods are discussed. The modeling method used in this paper is suitable for simulating the static performance of composite beams, especially in the investigation of the interface slip development.

Mechanical Behavior of Steel-Concrete Composite Beam Using Hat Shaped Steel Section

Mechanical Behavior of Steel-Concrete Composite Beam Using Hat Shaped Steel Section

Analysis of shear lag effect in the negative moment region of steel-concrete composite beams under fatigue load

Shear lag effect was a significant mechanical behavior of steel-concrete composite beams, and the effective flange width was needed to consider this effect. However, the effective flange width is mostly determined by static load test. The cyclic vehicle loading cases, which is more practical, was not well considered. This paper focuses on the study of shear lag effect of the concrete slab in the negative moment region under fatigue cyclic load. Two specimens of two-span steel-concrete composite beams were tested under fatigue load and static load respectively to compare the differences in the negative moment region. The reinforcement strain in the negative moment region was measured and the stress was also analyzed under different loads. Based on the OpenSees framework, finite element analysis model of steel-concrete composite beam is established, which is used to simulate transverse reinforcement stress distribution as well as the variation trends under fatigue cycles. With the established model, effects of fatigue stress amplitude, flange width to span ratio, concrete slab thickness and shear connector stiffness on the shear lag effect of concrete slab in negative moment area are analyzed, and the effective flange width ratio of concrete slab under different working conditions is calculated. The simulated results of effective flange width are compared with calculated results of the commonly used specifications, and it is found that the methods in the specifications can better estimate the shear lag effect in concrete slab under static load, but the effective flange width in the negative moment zone under fatigue load has a large deviation.

Behavior of Curved Steel-Concrete Composite Beams Under Monotonic Load

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.

A parametric study of steel-concrete composite beams with hollow core slabs and concrete topping

The use of industrialized elements results in the speed of execution, it avoids waste of materials, and it meets sustainability requirements. The steel profiles and hollow core slabs are included in this scope. The hollow core slab presents superior quality than cast in-situ structural elements, and it is produced in specific environments with technological control and monitoring. In general, a concrete topping is made for smooth and uniform finishing. Studies addressing the structural behavior of steel-concrete composite beams with hollow core slabs with concrete topping are scarce. The present work aims to investigate the behavior of steel-concrete composite beams with hollow core slabs with concrete topping, considering full and partial interaction. Geometric nonlinear analyses are performed based on experimental tests. The steel-concrete composite beams with hollow core slabs with concrete topping are simply supported and subjected to two points loads symmetrically spaced. The influence of concrete topping (50 mm of thickness), the in situ concrete strength (25 MPa, 30 MPa and 40 MPa), the transverse reinforcement diameter (10 mm, 12.5 mm and 16 mm), the interaction degree (shear connectors spaced at 120 mm, 175 mm and 225 mm), and the steel cross section (W360 × 51, W460 × 74 and W530 × 72) are the parameters investigated. The results are discussed, considering these parameters. It was concluded that the concrete topping increased the strength of the composite beams with precast hollow core slabs, the lower the degree of interaction, the greater the ductile behavior of the composite element as a whole. The in-situ infill concrete strength was directly influenced by the steel cross-sectional area, transverse reinforcement rate and interaction degree. The resistance of steel-concrete composite beams with precast hollow core slabs may vary depending on the transverse reinforcement rate and interaction degree. Ductile behavior was observed for all situations, considering partial interaction.

Experimental study on steel-concrete composite beams with Uplift-restricted and slip-permitted screw-type (URSP-S) connectors

In steel-concrete composite beams, to improve the cracking resistance of the concrete slab in the hogging moment region, a new type of connector in the interface, named uplift-restricted and slip-permitted screw-type (URSP-S) connector has been proposed. This paper focuses on the behavior of steel-concrete composite beams with URSP-S connectors. A total of three beam specimens including a simply supported beam with URSP-S connectors and two continuous composite beams with different connectors arrangements were designed and tested. More specifically, one continuous composite beam was equipped with URSP-S connectors in negative moment region and traditional shear studs in other regions. For comparison, the other one was designed with only traditional shear studs. The failure modes, crack evolution process, ultimate capacities, strain responses at different locations as well as the interface slip of the three tested specimens were measured and evaluated in-depth. Based on the experimental study, the research findings indicate that the larger slip deformation is allowed while using URSP-S connectors. Meanwhile, the tensile stress reduces and the cracking resistance of the concrete slab improves accordingly. In addition, the overall stiffness and strength of the composite beam become slightly lower than those of the composite beam using traditional shear studs. Moreover, the arrangement suggestion of URSP-S connectors in the composite beam is discussed in this paper for its practical design and application.