Steel-concrete Composite Beams Research Articles

Analytical Solution for Bending Deformation of Steel–Concrete Composite Beams Considering Nonlinear Interfacial Slip

Analytical Solution for Bending Deformation of Steel–Concrete Composite Beams Considering Nonlinear Interfacial Slip

A Numerical Study on the Influence of Bolt Corrosion on the Long-Term Behavior of Steel–Concrete Composite Beams

This study establishes a numerical model for beam-type steel–concrete composite specimens considering the corrosion of anchor bolts, with which studies the long-term deformation performance of the components under sustained load. The experimental results were compared with the calculated values obtained by combining the effective modulus method according to the CEB-FIP 1990 code and the ACI 209R code. Then a comparison with the calculation method of shrinkage and creep in standards (Standard Creep Method (SCM)) is made, and it shows that by supplementing the degradation of interface stiffness due to corrosion (using the defined modulus method (DMM)), the simulation results match better with the experimental results, confirming that this approach is suitable for analyzing the long-term load conditions of anchor bolt corrosion. Furthermore, based on the defined modulus method, the long-term behavior of composite beams under different loads and varying corrosion rates is studied.

Bending behaviour of steel–concrete composite beam with partial shear interface using MCS and ANN

Bending behaviour of steel–concrete composite beam with partial shear interface using MCS and ANN

A new method for rapidly capturing the strength and full nonlinear response of partially interacting steel–concrete composite beams

A semi-analytical procedure is presented for predicting the complete flexural response of partially interacting steel–concrete composite beams up to failure. The governing equation of the Euler–Bernoulli beam theory is solved wherein concrete, steel and the shear connectors joining the concrete slab to the steel beam are assumed to have nonlinear stress-deformation relationships. The adopted constitutive relationship for the connectors allows for partial or full composite action. The solution is applicable to beams and one-way slabs subjected to concentrated or uniform load and/or their combination. The governing equation is numerically solved by satisfying the equilibrium and compatibility requirements along the member. For the reinforced concrete part of the composite beam, a nonlinear moment–curvature relationship is developed that accounts for concrete nonlinearity in compression and for cracking and tension-stiffening in tension as well as for steel reinforcement nonlinearity. The steel profile is assumed to have a bilinear elasto–plastic strain-hardening moment–curvature relationship. Comparison of the proposed model results with the corresponding experimental load–deflection curves and interfacial shear–slip curves of several beams tested by others shows good agreement. The relative simplicity, efficiency and easy application of the present solution make it possible to accurately predict the failure load, interfacial slip and full nonlinear response of partially interacting composite beams.

Pull-out behavior of cluster stud-post pouring UHPC connectors in prefabricated steel-concrete composite beam

The use of ultra-high performance concrete (UHPC) as a connection material for cluster studs of prefabricated steel-concrete composite beams can achieve higher connection strength and less space for reserved holes. However, in addition to bearing the shear force, the studs need to bear the pull-out force to counteract the vertical relative separation between the steel and concrete. The pull-out behavior for cluster stud-post pouring UHPC connectors is complex and has not been clarified completely. Thus, a total of 30 cluster stud pull-out tests in 10 groups were carried out in this study, and the interface type, length-to-diameter ratio of the stud, transverse spacing of stud group, dimensions of the reserved holes, and type of post pouring concrete were considered. The results showed that the pull-out behavior of the cluster studs was different from that of studs embedded in cast-in-place intact UHPC slabs due to the UHPC conical integrity having been reduced significantly by the old-to-new concrete interface. The rough groove interface and UHPC as a post pouring material significantly improved the pull-out capacity and stiffness of the cluster studs. The stud fracture belongs to ductile failure, whereas UHPC and normal concrete (NC) cone failures are brittle. The bearing capacity of the UHPC cone is observed to increase with the effective embedment depth of the stud, the transverse spacing, and the dimensions of the reserved holes. The angle of the UHPC conical failure surface is 70° based on 3D laser scanning. Finally, the theoretical equations for predicting the pull-out capacity of stud-post pouring UHPC connectors with a rough groove interface were proposed, and the critical length-to-diameter ratio of the stud was calculated for different combinations of stud and UHPC strength.

Dynamic Response of Steel–Timber Composite Beams with Varying Screw Spacing

Steel–timber composite beams are a relatively new type of composite structure. They have many important advantages, owing to which they may be considered a sustainable solution. Their connectors may be demountable, which makes it possible to separate steel girders from LVL panels at the end of their service life. After disassembly, the structural elements can be recycled. One of their advantages is that they are lighter than steel–concrete composite beams. However, this may result in the poor performance of floors with steel–timber composite elements subjected to dynamic loadings. For this reason, the dynamic characteristics of floors should be investigated to verify the serviceability limit state of human-induced vibrations. In this study, the dynamic response of the three steel–timber composite beams with varying screw spacing was captured and used to validate their numerical models. The frequencies obtained from the numerical analyses correspond to the experimental results. A very high agreement between the vibration mode shapes was obtained because the MAC index values were close to 1. The validated numerical model of a single steel–timber beam may be used in future studies to create a complex numerical model of a steel–timber composite floor.

Driving adaptability of highway steel-concrete composite beam bridge with multiple damages: theory, technology and practice

ABSTRACT To enhance the post-disaster highway driving speed evaluation system for steel-concrete composite beam bridge (SCCBB), a human-vehicle-bridge coupled driving adaptability analysis method is proposed. This method integrates considerations of both driving safety and comfort. Numerical simulation is employed to utilize a damaged SCCBB as the engineering context for studying vehicle rollover safety, vibration acceleration limits, and driving comfort. The analysis considers various vehicle types, including sedan cars, mini vans, motor buses, and trucks, resulting in recommended speed limits for each category. The study reveals that trucks demonstrate lower susceptibility to rollover accidents compared to sedan cars, mini vans, and motor buses under constant damage grade and vehicle speed conditions. However, increased damage grade and road surface roughness elevate rollover risks and diminish driver comfort. To ensure smooth post-disaster traffic flow on SCCBB and maintain acceptable driving comfort and speed levels, it is recommended to enforce speed limits: below 60 km/h for sedan cars, below 40 km/h for mini vans and motor buses, and below 80 km/h for trucks. The primary aim of this study is to provide technical guidance for the safe operation and maintenance of post-disaster SCCBB.

Study on the shear behaviour of steel–concrete composite beams after elevated temperature and water cooling

Study on the shear behaviour of steel–concrete composite beams after elevated temperature and water cooling

Shear Performance of Demountable High-Strength Bolted Connectors: An Experimental and Numerical Study Based on Reverse Push-Out Tests

Steel–concrete composite beams, essential for large-span structures, benefit from connectors that reduce cracking at the supports. The crack resistance and alignment with sustainable building trends of high-strength bolted connectors have been extensively researched. Nevertheless, only a few studies exist on their load–slip behavior in hogging sections. In this study, the shear performance of high-strength bolted connectors subjected to tension due to hogging moments was studied based on experiments and numerical modeling according to numerous reverse push-out tests. The results revealed that tensile and splitting cracks were produced in the concrete. Their distribution was affected primarily by the concrete strength and bolt diameter; this distribution became denser at decreasing concrete strengths and increasing bolt diameters. Subsequently, an analysis of the out-of-plane displacement and load–slip response was performed to investigate the phenomenon of anchor rod sliding. A cost-effective and time-efficient finite-element (FE) model was developed to investigate the internal microstates of the specimens. It revealed a correlation between bolt cracking, specimen hardening, steel yield, and failure. A correction factor is also proposed for the shear capacity of bolts within concrete subjected to tension. The findings offer insights into the load–slip response of high-strength bolted connectors subjected to hogging moments, aiding in safer, more durable supports for steel–concrete composite beams.

Experimental study on fatigue behavior of prefabricated high-strength steel-concrete composite bridge beams

To investigate the fatigue performance of prefabricated high-strength steel-concrete composite beams (P-HS-CCB), six specimens were designed with different fatigue load amplitudes, different fatigue load upper limits, and varying degrees of shear connection. Among them, specimen S560 underwent static failure testing, while the remaining five specimens underwent fatigue testing. The analysis was conducted from the perspectives of fatigue failure modes, fatigue life, and stiffness after specific cycles, with a comparison of the fatigue life calculation formula from different international codes. The results demonstrate that the fatigue failure mode of the P-HS-CCB is cracking in the vicinity of the steel beam at the mid-span, followed by crack propagation along both the web and flange widths. The P-HS-CBB exhibits excellent combination effects and anti-fatigue performance, maintaining nearly constant stiffness during fatigue loading with minimal composite section slip. The fatigue life of the P-HS-CBB is mainly influenced by the fatigue load amplitude during the testing. The S-N curve provided by AASHTO shows a good fit with the curve fitting based on experimental data and can be used to guide the anti-fatigue design of this type of beam.

Study of Innovative Connector for Steel–Concrete Composite Structures

The paper presents an analysis of the innovative connector for manufacturing a steel–concrete composite beam. The connector consists of a corrugated metal sheet in the shape of a dovetail and shot nails. The nails are shot through the sheet fold into the flange of the steel I-section. Experimental studies of push-out tests were carried out. The conducted tests proved that the proposed solution can be applied as the fastener for steel–concrete composite beams for the construction of ceilings in utility public buildings with small beam’s span. Considering the criteria presented in the Eurocode 4 standard and the results of the experiments, it was proven that all analyzed types of fasteners are ductile. The connector made of sheet with a thickness of 1.00 mm and 2 nails is characterized by a breaking load of 30.83 kN. The load-bearing capacity of the fastener can be adjusted by changing the corrugated sheet thickness and changing the number of nails shot in the single fold of the sheet.

Driving Comfort Analysis Method of Highway Bridge Based on Human-Vehicle-Bridge Interaction

Research on evaluating highway bridge performance through vehicle-bridge interaction (VBI) analysis has made significant advancements. However, when assessing driving comfort, using vehicle acceleration instead of human acceleration poses challenges in accurately representing comfort. First, the paper proposes a finite element analysis method for human-vehicle-bridge spatial interactions (HVBSIs). Then, the importance of wheel path roughness difference is explored when assessing driving comfort. Furthermore, a new method for evaluating driving comfort that includes human and vehicle vibration responses has been proposed, and a simulation example of the steel-concrete composite beam bridge (SCCBB) is used to verify the effectiveness of the proposed method. The results demonstrate that the HVBSI analysis method effectively simulates the interconnected vibrations of the human body, the spatial vehicle model, and the three-dimensional (3D) bridge model. Differences in wheel path roughness significantly impact the roll vehicle vibration responses, which are crucial in driving comfort analysis. The driver’s body vibration response is essential for evaluating driving comfort, and its inclusion leads to increased comfort indices values. In comparison to traditional methods, the overall vibration total value (OVTV) increases by a maximum of 109.04%, and the level of weighted vibration (Leq) increases by a maximum of 6.74%. This leads to an upgrade from grade IV to grade V in terms of comfort level, indicating a reduced comfort.

A Detailed Numerical Model for a New Composite Slim-Floor Slab System.

The paper concerns the numerical modelling of a new slim-floor system with innovative steel-concrete composite beams called "hybrid beams". Hybrid beams consist of a high-strength TT inverted cross-section steel profile and a concrete core made of high-performance concrete and are jointed with prestressed hollow core slabs by infill concrete and tie reinforcement. Such systems are gaining popularity since they allow the integration of the main structural members within the ceiling depth, shorten the execution time, and reduce the use of concrete and steel. A three-dimensional finite element model is proposed with all parts of the system taken into account and detailed geometry reproduction. Advanced constitutive models are adopted for steel and concrete. Special attention is paid to the proper characterisation of interfaces. The new approach to calibration of damaged elastic traction-separation constitutive model for cohesive elements is applied to concrete-to-concrete contact zones. The model is validated with outcomes of experimental field tests and analytical calculations. A satisfactory agreement between different assessment methods is obtained. The model can be used in the development phase of a new construction system, for instance, to plan further experimental campaigns or to calibrate simplified design formulas.

Development and assessment of sustainable steel-concrete composite beams with novel demountable shear connections

The design of sustainable steel-concrete composite beams (SSCCBs) with demountable shear connections (DSCs) for deconstructability can improve the problem of construction and demolition waste during these construction activities, and it also strengthens the sustainability of a building by allowing for easy dismantling and the reuse or recycling of structural components at the service load and easy replacing the damaged members to achieve the resilience capacity after earthquake. In this study, the structural configuration and concept design of novel SSCCBs using DSCs were firstly introduced. The nonlinear finite element models (FEMs) using the Abaqus software were validated in terms of the load versus mid-span deflection curves and failure modes of the similar composite beams given by the experimental data. A parametric study was implemented to identify the influence of the following variables: geometric size, strength grade, inclination angle and shape of concrete plug, diameter and strength grade of connected bolt, steel grade and width and grade of slab concrete. It was found that geometric size, grade and smooth shape of concrete plug could optimize the performance level of occupancy while bolt diameter and grade enhanced the reuse behavior at service loads. Additionally, increasing the bolt diameter and steel grade led to an increase by 8–10% in the equivalent ultimate strength and to decrease the ductility of the whole beams obviously. Bolt diameter, steel grade and slab width have quite influences on the stiffness due to increase the interaction degree of these prefabricated components. Based on the theoretical and parametric analysis results, simple design method of ultimate moment capacity for this SSCCBs with DSCs is proposed to facilitate design practice.

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.

Cracking performance in the hogging moment region of HSS-UHPC continuous composite girder bridges

To elucidate the cracking performance of concrete slabs at the negative bending moment region of high strength steel (HSS)-ultra high performance concrete (UHPC) continuous composite girder bridges, eight scale-reduced steel-concrete composite beams, constructed using HSS and UHPC that varying parameters of UHPC slab thickness and width and shear connection degree at the steel-concrete interface were prepared and tested. The composite beams' cracking pattern, bending stiffness, load-deflection curve, steel-concrete interfacial slippage, and strain history were presented and discussed. The test results show that the HSS-UHPC composite beams subjected to negative bending moments exhibited favorable cracking performance. With the UHPC slab width increasing from 450 mm to 550 mm, the composite beams' initial cracking moment, bending stiffness, and flexural ductility increased by 33.4%, 20.5%, and 39.8%, respectively. The utilization of a thick UHPC slab benefited the performance of the composite beams under negative bending moments. Replacing the 80 mm-thick slab with a 110 mm-thick slab improved the structure’s cracking moment and bending stiffness by 15.0% and 21.4%, respectively. Additionally, as the shear connection degree increases from 0.64 to 1.02, the initial cracking and ultimate failure moments of the composite beam were improved by 7.2% and 1.6%, respectively. In contrast, the bending stiffness of the beams with a shear connection degree of 1.02 was 12.4% smaller than those of 0.64. A comprehensive comparison between the formula-predicted cracking performance and current experimental results was performed to examine the capability of existing design approaches in calculating the HSS-UHPC composite beams. The flexural resistance algorithm proffered by Xu exhibits favorable alignment with test results, thereby providing a compelling methodology for designing HSS-UHPC continuous composite girder bridges.

Shear Behavior and Design of Innovative Stud-Reinforced Embedded Shear Connectors with Flanges

The embedded shear connector with flanges (ESCF) exhibits excellent shear performance in the steel–concrete composite beam. The ESCF consists of embedded corrugated steel web as the shear connector and shape-matched flanges for construction convenience. However, previous research showed that the steel flange of the ESCF was prone to local buckling when subjected to shear force, resulting in insufficient shear strength of the connector. In this paper, head studs were adopted to reinforce the ESCF at the flange with a large width-to-thickness ratio. Nine stud-reinforced embedded shear connectors with flanges (SR-ESCF) were manufactured to conduct the push-out test to investigate the shear performance of SR-ESCF. The effects of the reinforcing studs, thickness of the web, width-to-thickness ratio of the flange, embedding depth of the web, and diameter of the combined rebar on shear strength of the SR-ESCF were revealed and discussed thoroughly. The push-out test results showed that the head studs significantly improved the initial stiffness and load-bearing capacity of the ESCF, which were increased by 17% and 15%, respectively. Moreover, the head studs prevented local buckling of the steel flange. The shear strength of the specimens was greatly influenced by the embedding depth of the web, the width-to-thickness ratio of the flange as well as the reinforcing studs. However, the diameter of the combined rebar and thickness of the web had negligible effects on the shear capacity of the SR-ESCF. According to the test results, the nonlinear finite element model (FEM) and the shear capacity of SR-ESCF prediction formula were created and verified. Furthermore, the layout of the reinforcing studs welded on the flange of the SR-ESCF was optimized by the validated FEM, which indicated that the shear-bearing capacity of the SR-ESCF could be significantly increased by adding studs on the steel flange near the original studs. This research will be of great significance to the design and implementation of the steel–concrete composite beam bridge with corrugated steel web.

Some issues about the behaviour of external pre-stressed steel–concrete composite beams

A numerical experiment is performed to evaluate the behaviour of externally pre-stressed steel–concrete composite beams (EPSCCBs) up to their ultimate stages, considering second-order effects, tendon material and friction at tendon–deviator locations. The tendon force evolution with loading and slip at the steel–concrete interface is explored. A three-dimensional finite-element model is used to include all these aspects. The idea is to deconstruct the project of eight experimental EPSCCBs with different tendon profiles, considering the above-mentioned issues. The main findings indicate that the inclusion of second-order effects is essential for predicting the stress paths near the collapse loads and slip demands at the steel–concrete interface, while external tendons made of carbon fibre-reinforced polymer (CFRP) can be used as a substitute for classical steel ones, as they presented similar behaviours. The largest tendon force increments occurred for the CFRP tendons compared to other tendons made of glass, aramid and basalt fibre-reinforced polymers. Furthermore, it was found that a friction coefficient between 0.2 and 0.4 at the tendon–deviator interface better matches the available experimental tendon force evolution with loading. This finding seems to counteract the common assumption of using a null friction coefficient as suggested in other works.

Experimental and numerical investigation of steel–concrete composite beam subjected to contact explosion

The steel–concrete composite beam, consisting of a concrete slab, a steel beam, and shear connectors, is extensively utilized in bridge engineering due to its effective utilization of material properties and convenient construction. Considering the significant impact of explosive incidents on bridge safety, and the limited experimental research on blast performance of composite beams, this study tested three small-scale SC composite beams arranged with commonly used shear connectors, including studs, PBL ribs, and combination connectors, under contact explosion with 200 g of TNT. Finite element (FE) models, validated by the experimental data, were established to conduct damage analysis to understand the damage mode and characteristics of SC composite beams. The results showed that the SC composite beams exhibit a localized damage pattern concentrated in the mid-span of the beams under contact explosions. The concrete spalling on the bottom surfaces could be divided into two parts by the top flange of the steel beam. The concrete slab, which absorbs more than 94 % of the total internal energy of the SC composite beams, plays the most important role in reducing the damage to the beams under contact explosion. In some aspects, the type of shear connectors influences the crack pattern, concrete spalling degree, the deformation of the steel beam, and the difference in acceleration response between the concrete slab and steel beam, but on the whole, it has a limited effect on the damage mode and degree of SC composite beams subjected to contact explosion.

Data-driven design approach for the lateral-distortional buckling in steel-concrete composite cellular beams using machine learning models

Composite steel-concrete beams are presented as an interesting solution for covering long spans. These profiles are characterized by the existence of sequentially spaced openings along the beam web. A very common particular use of this type of structure is in continuous or semi-continuous floors, in which the existence of intermediate supports in the span of the structural member leads to the occurrence of points with negative bending moment. Steel structures in this condition can present different types of instability due to the compression of the bottom flange, such as lateral-distortional buckling and web-post buckling. In this context, a comprehensive parametric study was carried out through finite element simulation aiming to obtain the resistance capacity of this type of structural system. It was observed that different analytical procedures aimed at calculating the ultimate moment of this type of structure fail to predict the bearing capacity of the elements successfully. Thus, aiming to promote more precise design approaches, the modeling of the resistant load of these structures was performed using different supervised machine learning techniques. It was found that machine learning techniques have the potential to correctly predict the bearing capacity of the studied members, having a better agreement with the numerical data obtained, when compared to the approaches presented by analytical procedures described in the literature and design codes. Different machine learning algorithms were trained based on a dataset obtained via FEM: artificial neural networks, support vector machines, XGBoost and Random Forest. All models showed considerable effectiveness, with statistical determination coefficients (R²) higher than 0.9. Among these, the best prediction capacity was obtained with the XGBoost model in terms of correlation coefficient and Mean Square Error, presenting itself as the model that came closest to the set of numerical data used as reference.