Steel-concrete Composite Deck Research Articles

Nonlinear Analysis of Steel-Concrete Composite Deck Considering Interfacial Slip and Uplift

Nonlinear Analysis of Steel-Concrete Composite Deck Considering Interfacial Slip and Uplift

Design and construction of a railway flyover at Hitchin, UK

A new 837 m long elevated railway has been built at Hitchin in the UK to carry trains between London and Cambridge over the East Coast Main Line. It relieves the main bottleneck at the junction where Cambridge line trains cross the East Coast route on a flat junction. The project involved the design and construction of a 29-span viaduct made of a steel–concrete composite deck, which is effectively composed of 15 jointed structures. Twelve of these are made of two continuous 30 m spans, two structures are made of single, simply supported spans and the remaining length is a continuous three-span structure with a maximum central span of 60 m that crosses the railway at a skew angle of more than 60°. The 425 m curved plan radius alignment was a design challenge as significant torsional effects are caused by the plan curvature, the eccentricity of applied vertical actions, the centrifugal effects and the wind pressures acting on the trains. Steel erection started with the main railway spans, a process that took three overnight possessions due to the curvature, the heavy skew and the geometry of the girders. This paper describes the critical design aspects and the main construction operations of the flyover.

Experimental Investigation on Shear Connectors in Steel-concrete Composite Deck Slabs

Background/Objectives: The steel-concrete composite construction has become an effective construction practice in the recent years. The cold form profiled sheet acts a platform for during the construction phase and acts as an external reinforcement after the construction. In steel-concrete composite construction, the shear connectors transfer the longitudinal shear force across the steel flange/concrete interface. The ability to transfer longitudinal shear force by shear connectors mainly depends on the strength of concrete against longitudinal cracking and mechanical properties of the shear connectors. This research investigates shear connector's capacity; the experimental investigation is involved using push-out test for two sets with different shear connectors framing to the profile steel sheet. Methods/Statistical Analysis: Set-W consists of three composite slab specimens with welded stud shear connectors, while set-B consists of three composite slab specimens with bolted shear connectors. Trapezoidal profile steel sheet of thickness 1 mm with rectangular embossments is used. Several key parameters of the composite slab are examined and measured, including slippage capacity, load carrying capacity, composite slab ductility and failure mechanism. Findings: the welded shear connectors provided a better performance in resisting slippage and providing a welded set higher load carrying capacity, however, the bolted shear connector specimens set showed more ductile behavior as compared to of specimens.

Interfacial Behavior of Steel-Concrete Composite Deck by Fiber Bragg Grating Sensors

Interfacial Behavior of Steel-Concrete Composite Deck by Fiber Bragg Grating Sensors

Analysis of concrete shrinkage along truss bridge with steel-concrete composite deck

The paper concerns analysis of effects of shrinkage of slab concrete in a steel-concrete composite deck of a through truss bridge span. Attention is paid to the shrinkage alongside the span, i.e., transverse to steel-concrete composite cross-beams. So far this aspect has not been given much attention in spite of the fact that it affects not only steel-concrete decks of bridges but also steel-concrete floors of steel frame building structures. For the problem analysis a two-dimensional model is created. An analytical method is presented in detail. A set of linear equations is built to compute axial forces in members of truss girder flange and transverse shear forces in steel-concrete composite beams. Finally a case study is shown: test loading of twin railway truss bridge spans is described, verified FEM model of the spans is presented and computational results of FEM and the analytical method are compared. Conclusions concerning applicability of the presented analytical method to practical design are drawn. The presented analytical method provides satisfactory accuracy of results in comparison with the verified FEM model.

Dynamic behaviour of steel–concrete composite under-deck cable-stayed bridges under the action of moving loads

The dynamic response of under-deck cable-stayed bridges with steel–concrete composite decks under moving loads is presented, and different parameters are considered. The vibrational modes with a strong contribution in the response, the key parameters that control the modal frequencies, and those that reduce the maximum accelerations registered on the deck in a cost-effective manner, are identified. It is found that relatively high accelerations occur and that these can be increased by large load eccentricities. It is also found that maximum accelerations are conditioned by the amplification and cancellation speeds of the loads. Increasing the depth of the deck is determined to be the most effective way to reduce the maximum accelerations. Decks formed by I-beams seem to be quite appropriate from the perspective of dynamic behaviour, while box sections tend to increase the overall cost of the bridge. The findings provide effective strategies to define the most efficient configurations that satisfy the limit state of vibrations, which is critical for this type of bridge.

Equivalent moment of inertia of a truss bridge with steel-concrete composite deck

Flexural stiffness of bridge spans has become even more important parameter since Eurocode 1 introduced for railway bridges the serviceability limit state of resonance. For simply supported bridge spans it relies, in general, on accurate assessment of span moment of inertia that governs span flexural stiffness. The paper presents three methods of estimation of the equivalent moment of inertia for such spans: experimental, analytical and numerical. Test loading of the twin truss bridge spans and test results are presented. Recorded displacements and the method of least squares are used to find an experimental moment of inertia. Then it is computed according to the analytical method that accounts for joint action of truss girders and composite deck as well as limited span shear stiffness provided by diagonal bracing. Finally a 3D model of finite element method is created to assess the moment of inertia. Discussion of results is given. The comparative analysis proves efficiency of the analytical method.

Simplified analysis method accounting for shear-lag effect of steel–concrete composite decks

Due to the influence of steel beam web, the concrete slab and steel box-beam flange would undergo significant warping in steel–concrete composite decks with wide slab. Such mechanical behavior is referred as the shear-lag effect and often calculated by adopting effective width. There arises a necessity to propose a simplified analysis method based on effective width to account for the shear-lag effect of composite decks, which would greatly assist in design analysis as it is easy to use in a general beam element model. In this paper, the static tests are carried out on a composite twin I-girder deck and a composite box-girder deck specimens. These two specimens are subjected to vertically flexural and axially compressive loads in the tests. An elaborate element model is later built and utilized to analyze the shear-lag effect of composite decks. Through elaborate element model analysis on composite decks subjected to vertically flexural and axially compressive loads, respectively, the longitudinal distribution characteristic of effective width are determined. Furthermore, the prediction formulae of effective width are proposed. Finally, based on a general beam element model, the simplified analysis method of a composite continuous I-girder deck for the design process is performed taking into consideration three load cases, which include gravity load, traffic load envelope and prestressing load.

An innovative steel-concrete joint for integral abutment bridges

Integral abutment bridges are becoming rather common, due to the durability problems of bearings and expansion joints. At the same time, among short- and medium-span bridges, multi-beam steel-concrete composite deck with hot-rolled girder is an economical and interesting alternative to traditional pre-stressed concrete solutions. The two concepts can be linked together to design integral steel-concrete composite bridges with the benefits of two typologies. The most critical aspect for these bridges is usually the joints between deck and piers or abutments. In this paper, an innovative beam-to-pier joint is proposed and a theoretical and experimental study is introduced and discussed. The analyzed connection is aimed at combining general ease of construction with a highly simplified assembly procedure and a good transmission of hogging and sagging moment at the supports in continuous beams. For this purpose, the traditional shear studs, used at the interface between steel beam and upper concrete slab, are also used at the ends of steel profiles welded horizontally to the end plates. To better understand the behaviour of this kind of joints and the roles played by different components, three large-scale specimens were tested and an FE model was implemented. The theoretical and experimental results confirmed the potential of the proposed connection for practical applications and indicated the way to improve its structural behaviour.

Analysis of Shrinkage and Creep Effects on New Steel-Concrete Composite Deck System for Suspension Bridge

AbstractTo study the shrinkage and creep of the new steel-concrete composite deck system of a suspension bridge, an equivalent calculation method based on the existing calculation theory of shrinkage and creep with changing temperatures and creep guidelines was proposed. Two different validation analysis models were established for the same structure using two largely popular finite element programs. The validity and accuracy of the equivalent results were verified, and the equivalent method was found to be practical, feasible, and highly accurate. A fine segment model for the steel-concrete composite bridge deck system of a suspension bridge was created with the use of the ANSYS finite element program. Further research was conducted on the effect of shrinkage and creep on a composite structure using the proposed equivalent calculation method. Research results for the new class of steel-concrete composite bridge deck indicate that the concrete shrinkage effect is dominant, but the creep effect is relative...

Structural Aspects of Railway Truss Bridges Affecting Transverse Shear Forces in Steel-Concrete Composite Decks

Abstract At the steel-concrete interface, the horizontal shear forces that are transverse to cross beams occur due to joint action of the steel-concrete composite deck and the truss girders. Numerical analysis showed that values of the forces are big in comparison to the longitudinal shear forces. In both cases extreme force values occur near side edges of a slab. The paper studies possibilities of reduction of these shear forces by structural alterations of the following: rigidity of a concrete slab, arrangement of a wind bracing, arrangement of concrete slab expansion joints. An existing railway truss bridge span has been analysed. Numerical analysis shows that it is possible to reduce the values of shear forces transverse to cross beams. It may reach 20% near the side edges of slabs and 23% in the centre of slab width.

Mechanical characteristics of hollow shear connectors under direct shear force

The steel-concrete composite decks have high fatigue durability and deformability in comparison with ordinary RC slabs. Withal, the steel-concrete composite deck is mostly heavier than the RC slabs. We have proposed herein a new type of steel-concrete composite deck which is lighter than the typical steel-concrete composite decks. This can be achieved by arranging hollow sectional members as shear connectors, namely, half-pipe or channel shear connectors. The present study aims to experimentally investigate mechanical characteristics of the half-pipe shear connectors under the direct shear force. The shear bond capacity and deformability of the half-pipe shear connectors are strongly affected by the thickness-to-diameter ratio. Additionally, the shear strengths of the hollow shear connectors (i.e. the half-pipe and the channel shear connectors) are compared. Furthermore, shear capacities of the hollow shear connectors equivalent to headed stud connectors are also discussed.

Road Bridges WD7-WD8 on Route Sucharskiego, Poland - Innovative Steel-Concrete Composite Deck Solutions

In the range of small- and medium-span bridges, multi-beam steel–concrete composite decks consisting of high-strength hot-rolled girders are an economical and interesting alternative to traditional pre-stressed concrete solutions. The use of reinforced concrete cross-beams at the supports allows for a further optimization because of the easy and simple construction. This deck typology was introduced in Europe already in the 1990s and is now becoming a common solution for many standard bridges. This article describes the application of this typology to some of the viaducts on Route Sucharskiego, Poland. The principles of the deck concept, steel grade choice, concrete cross-beam function, fabrication detailing and construction phase are described in detail.

Mechanical behavior of steel-concrete composite decks with perfobond shear connectors

Exodermic deck systems are new composite steel grid deck systems which have been used in various projects during the past decade. One of the eminent features of this system is considerable reduction in the structure weight compared to the ordinary reinforced concrete decks and also reduction in construction time by using precast Exodermic decks. In this study, dynamic properties of the Exodermic deck bridges with alternative perfobond shear connectors are investigated experimentally. In order to evaluate the dynamic properties of the decks, peak picking and Nyquist circle fit methods are employed. Frequencies obtained experimentally are in good agreement with the results of the finite-element solution, and the experimental results show that the first mode is the most effective mode among the obtained modes. The first four modes are the rigid translational motion modes, and the next two modes seem to be rigid rotational motion modes around a horizontal axis. From the 7th mode onwards, modes are flexible. The range of damping ratios is about 0.5%. Furthermore, the static behavior of the Exodermic decks under a static load applied at the center of the decks was investigated. Failure of the decks under positive bending was punching-shear. The bending strength of the decks under negative bending was about 50 percent of their strength under positive bending. In addition, the weight of an Exodermic deck is about 40% of that of an equivalent reinforced concrete slab.

Composite deck in two-dimensional modelling of railway truss bridge

The paper shows a technique of two-dimensional modelling of railway truss bridge girders. The model accounts for joint action of girders and steel-concrete composite deck. Namely, influence of the deck on span flexural rigidity and internal force distribution in truss members are taken into account. The technique is capable of reflecting various arrangements of cross beam to truss flange connection as well as various concrete slab longitudinal rigidity (uncracked/cracked). Application example of test loaded bridge span is given. The accuracy of assessment of span flexural stiffness and internal forces distribution of presented procedure is similar to 3D beam/shell element model results accuracy. The presented technique is suitable for preliminary design of truss bridges and verification of other computational methods.

Heat conduction analysis of steel-concrete composite decks under freeze-thaw environment

Heat conduction analysis of steel-concrete composite decks under freeze-thaw environment

Recent research of shear connection in prefabricated steel-concrete composite beams

Prefabrication of steel-concrete composite decks can improve their competitiveness and sustainability. This paper presents recent studies of longitudinal shear connection at the University of Belgrade, Faculty of Civil Engineering. Grouped welded headed studs and bolted shear connectors, suitable for prefabricated composite construction, has been examined in push-out tests. Totally 30 tests were conducted, and advanced FEA were made using Abaqus/Explicit dynamic solver. Based on the experimental and numerical studies behaviour those two shear connectors are compared.

Fatigue of headed studs welded with improved ferrules under rotating shear force

This paper presents an evaluation of the fatigue strength of headed studs welded with improved ferrules under rotating shear force. In steel–concrete composite structures, shear connectors are essential components to transfer shear forces at the interface between steel and concrete. Particularly, headed studs in steel–concrete composite decks for highway bridges are subjected to rotating shear force when vehicle loads pass through the steel–concrete composite decks. The authors have developed welding ferrules for headed studs with higher fatigue duration than conventional headed studs. In this study, the rotating shear force was applied to the improved headed studs by using a specially developed testing machine in order to determine the fatigue strength in association with the concrete strength. The fatigue strength of the headed studs increased with the higher concrete strength and two failure modes were observed. Finally, the average S–N curves in correspondence with concrete strengths were determined for the improved headed studs.

Investigations on Efficiently Interfaced Steel Concrete Composite Deck Slabs

The strength of the composite deck slab depends mainly on the longitudinal shear transfer mechanism at the interface between steel and concrete. The bond strength developed by the cement paste is weak and causes premature failure of composite deck slab. This deficiency is effectively overcame by a shear transferring mechanism in the form of mechanical interlock through indentations, embossments, or fastening studs. Development of embossment patterns requires an advanced technology which makes the deck profile expensive. Fastening studs by welding weakens the joint strength and also escalates the cost. The present investigation is attempted to arrive at a better, simple interface mechanism. Three types of mechanical connector schemes are identified and investigated experimentally. All of the three shear connector schemes exhibited full shear interaction with negligible slip. The strength and stiffness of the composite slabs with shear connectors are superior about one and half time compared to these of the conventional reinforced concrete slabs and about twice compared to these of composite slabs without mechanical shear connectors. The scheme2 and scheme3 shear connector mechanisms integrate deck webs and improve strength and stiffness of the deck, which can effectively reduce the cost of formworks and supports efficiently.

Influence of Concrete Shrinkage and Creep on Composite Beam of Cable-Stayed Bridge

Based on the shrinkage and creep theory model of the JTG D62-2004 and trough the finite element analysis software, it is to respectively calculate the main span displacement and the upper and lower edge stress of the steel beam and the concrete slab under the impacts of concrete shrinkage and creep at the initial stage and the normal operation stage (with 10 years of shrinkage and creep calculated) for the steel-concrete composite deck system of the cable-stayed with a main beam of 436m.The results show that the effects of the shrinkage and creep can’t be ignored.