Steel-concrete Composite Bridge Research Articles

Mechanical behavior of asphalt pavement on steel-concrete composite beam bridge under temperature-load coupling

Over the past few decades, steel–concrete composite beam (SCCB) bridges have been gaining popularity all over the world. However, distresses such as rutting, delamination and cracking may occur on the corresponding bridge pavement structure soon after open traffic. To alleviate pavement distresses and clarify the applicability of different pavement structures and materials, in this study, a targeted research method for the mechanical properties of SCCB bridge deck pavement under temperature-load coupling was proposed. The research elements and procedures of the SCCB bridge deck pavement were structurally analyzed and synthesized. In addition, a temperature-load coupling model of SCCB bridge deck pavement was established. The permanent deformation under different cumulative axle load action times was calculated and fitted, and then compared with the actual detected data. Finally, the mechanical response of pavement structures commonly used for SCCB bridges was analyzed. The results show that the absolute error of rutting depth between the field test and fitting result was small, which proved the rationality of the proposed method. Besides, for SCCB bridges, “AC + SMA” and “double-layer SMA” have better road performance. The conclusion of this paper provides reliable support for the maintenance and distress causes analysis of SCCB bridge deck pavement.

Influence of longitudinal prestress on the shear resistance of prefabricated shear stud connectors

In order to meet the requirements of accelerated bridge construction (ABC), the structure of steel–concrete composite bridges presents a development trend of the entire assembly. A Prefabricated Composite Shear Studs (PCSS) is proposed to speed up the assembly efficiency of traditional steel–concrete composite beams and improve the effectiveness of the prestress of prefabricated concrete decks in the negative moment zone. A finite element model (FEM) of the PCSS shear connector is established by considering the stress characteristics of different assemblies, thirty different steel tendon quantities, and relative arrangements are selected to analyse the impact of longitudinal prestress on the shear resistance of PCSS, the effectiveness of finite element model is verified this through test results. It is revealed that the steel tendon arrangement and quantity will change the shear resistance of the PCSS shear connectors. However, the magnitude, positive and negative effects are related to the position of the steel tendon along the deck height. When the steel tendon deviates downward from the neutral axis of the deck, the shear bearing capacity and shear stiffness increase; in addition, its force transfer mechanism is that the longitudinal prestress changes the lateral restraint effect of the PCSS on the concrete. Under the combined action of prestressing and transverse restraint of steel plate, the cooperative working ability of the stud and surrounding concrete can be enhanced or weakened. Thus, the yielding of stud and concrete damage can be delayed or accelerated, significantly affecting the shear bearing capacity and stiffness.

Design and Optimization of the Bi-Directional U-Ribbed Stiffening Plate–Concrete Composite Bridge Deck Structure

The steel–concrete composite structure is widely used in civil engineering for large-span bridges. Orthotropic steel bridge decks (OSDs) have particularly gained popularity due to their excellent mechanical performance. To address cracking issues in OSDs and concrete in negative moment regions, a novel bi-directional U-ribbed stiffening plate (BUSP)–concrete composite bridge deck is proposed. By using finite element analysis, the mechanical performance is evaluated based on maximum tensile stress and vertical displacement of concrete overlays. Results show that the BUSP–concrete deck outperformed conventional flat decks. It is also found that increasing the height, thickness, and opening width of U-ribs reduced tensile stress and maximum displacement. Adjusting height had the most significant effect on displacement while opening width affected tensile stress the most. Considering material usage, optimizing height is proved to be more effective than adjusting thickness and opening width. Decreasing spacing parameters improved performance but added complexity and reduced construction convenience. These findings will guide the design and optimization of steel–concrete composite bridge deck structures.

Experimental and numerical studies on shear stud connectors under combined shear and tension force

Shear stud connections have been widely used in steel–concrete composite bridges, while research on shear studs under combined shear and tension force is still lacking. In this research, 18 specimens, including sixteen push–out specimens under different tension force ratios and two pull–out specimens were tested to study the failure modes, load–slip curves and shear capacity of shear stud connectors under combined shear and tension force. The experimental results show that both the shear capacity and shear stiffness decrease remarkably as the tension force ratio rises. The maximum reduction in shear capacity and in shear stiffness are 37.0% and 68.9%, respectively, when tension force ratio rises from 0 to 0.6. Shear slip and necking are both demonstrated in the failure mode of shear stud connectors when shear and tension forces are coupled. Numerical models were established using ABAQUS and verified by the experimental data to investigate the influence of concrete strength, reinforcement ratio and stud diameter thoroughly via parametric analysis. The results indicate that the shear capacity of shear stud connectors increases as concrete strength and stud diameter rise. Higher concrete strength and closer reinforcement spacing offer better collaborative deformation ability between the studs and the surrounding concrete, and also develop the ratio of the shear capacity under combined shear and tension force to the shear capacity under uniaxial shear force ( Vu/ Vuu). Equations to give prediction of the shear capacity integrated with concrete strength enhancement factor and to describe the load–slip curves of shear stud connectors under combined shear and tension force were proposed and proved to be more accurate.

Hybrid machine learning model for prediction of vertical deflection of composite bridges

A novel hybrid model, based on machine learning technique, for quick and accurate prediction of the vertical deflection of steel–concrete composite bridges was developed. The model is a combination of a bagging (B) ensemble and an instance-based k-nearest neighbours (IBk), hence called the B-IBk. In the models, five easily determined input parameters (cross-sectional shape, concrete beam length, age of the bridge, height of main girder and distance between main girders) are used to obtain the output parameter (maximum vertical deflection). To develop the models, direct measurement data from 83 steel–concrete composite bridges located at different places in Vietnam were collected and used as input and output parameters. Standard statistical evaluation indicators (mean absolute error, correlation coefficient (R) and root mean square error) were used to validate and compare the models’ performance. The results showed that the performance of the novel hybrid model (B-IBk) for predicting the maximum vertical deflection (Y) of steel–concrete composite bridges was very good (R = 0.908) and better than that of the single IBk model (R = 0.875) on the testing dataset. The developed novel model is thus a promising tool for accurate prediction of the Y of steel–concrete composite bridges.

Numerical study of seismic performance of steel-concrete composite rigid-frame bridge with precast segmental CFDST piers crossing fault-rupture zones

Although seismic performance of bridges crossing fault-rupture zones has been studied in recent two decades, there is still no effective solution to mitigate the hazard of fault-crossing effect. Recently, a new type of post-tensioned precast segmental (PTPS) concrete-filled double skin steel tube (CFDST), known as PTPS-CFDST column, has been proposed and verified to exhibit excellent performance with respect to seismic resilience. Moreover, PTPS-CFDST columns can accommodate torsional deformation through joint slip and are thus considered as a promising structural solution for bridges crossing fault-rupture zones. This study aims to investigate the performance of a steel–concrete composite rigid-frame bridge (SCCRFB) with PTPS-CFDST piers subjected to across-fault ground motions through numerical simulations. Two detailed three-dimensional (3D) finite element (FE) bridge models are developed using the explicit FE code LS-DYNA. In particular, Bridge 1 uses the new PTPS-CFDST pier, while Bridge 2 serves as a reference model with monolithic CFDST piers. Two types of across-fault ground motions with strike- and dip-slip mechanisms are used as seismic inputs, and the influence of fling-step is parametrically investigated. Structural responses, including the global seismic responses, seismic damages, energy absorption, and local joint slip and opening, are systematically discussed. The numerical results indicate that, compared to the monolithic CFDST piers, PTPS-CFDST piers exhibit advantages in terms of seismic resilience, with lower damage and outstanding self-centering performance, which facilitates post-earthquake recovery after experiencing across-fault ground motions. This study provides valuable references for the seismic design of bridges with PTPS-CFDST piers crossing fault-rupture zones.

Shear Performance of Epoxy Joints in a Precast Bridge Deck Considering Constraint Effects.

The joint form plays a vital role in the rapid assembly of precast bridge decks for steel-concrete composite bridges. Existing research primarily focuses on studying the shear performance of joints through direct shear tests, which is insufficient to fully reflect the mechanical behavior of joints under the constraint of prefabricated bridge deck panels during actual vehicular traffic. Considering situations such as vehicle loads and external forces acting on precast bridge decks, this study investigates the shear performance of epoxy joints under constraint through an improved shear test. The influence of constraint force, shear key details and interface defects on the shear performance of epoxy joints is investigated. The results reveal that the shear test method employed in this study can realistically reflect the shear performance of epoxy joints in precast bridge decks. Both active and passive constrained epoxy joint specimens exhibited no interface cracks, and their failure modes were identified as shear failure between mid-span supports. Compared with passive constraint, the shear-bearing capacity of epoxy joint specimens under active constraint was increased by 86.1~130.6%. Among the epoxy joint specimens with depth-height ratios of 15/110, 25/110, 35/110 and 45/110, the joint with a depth of 35 mm demonstrated the highest shear strength. Furthermore, the shear performance of epoxy joints significantly deteriorated when the interface defects exceeded 30%, resulting in the failure mode transforming from shear failure to interface failure.

Advances in Methodology for Fatigue Assessment of Composite Steel–Concrete Highway Bridges Based on the Vehicle–Bridge Dynamic Interaction and Pavement Deterioration Model

Fatigue cracking is one of the most prominent causes of mechanical failure limiting the service life of existing steel and composite steel–concrete bridges and is among the central concerns of structural and bridge engineers. In this context, the current work presents some recent advancements in an existing methodology for fatigue analysis developed by the authors throughout the years. The methodology is specifically devoted to the fatigue assessment of composite steel–concrete bridges employing the local hot-spot S-N approach and a coupled vehicle–pavement–bridge system considering progressive pavement deterioration with stochastically generated roughness profiles. Two different methodologies were used to solve the dynamic equilibrium equations: the modal superposition method to solve the bridge dynamic equations and a direct integration method to solve the vehicle dynamic equations. From a computational point of view, the present approach is more efficient and detailed than previous versions, as it allows a significant reduction in the analysis time and the use of complex bridge and vehicle finite element models. In this regard, a case study of a highway composite steel–concrete bridge spanning 40 m was selected in order to demonstrate the usefulness of the presented improved methodology by carrying out a fatigue analysis. The results of this investigation (displacements and stresses) are presented, aiming to verify the factors that directly influence the structural response and, consequently, the service life of steel–concrete composite highway bridges.

Fuzhou–Xiamen high-speed railway: a new paradigm for China’s cross-sea railways

The new 277 km Fuzhou–Xiamen high-speed railway in China is the country’s first cross-sea railway designed for operational speeds of 350 km/h. Completed in 2023, it involved various advanced construction technologies, including the world’s first 1000 t bridge-building machine to be used offshore, advanced corrosion-resistant steel, pioneering rotation of a main bridge pylon, and aerodynamic steel–concrete composite bridge decks with ballastless tracks. The innovative project represents a milestone for China’s high-speed railway, heralding a new era of cross-sea transportation.

Deck Slab Elements for the Accelerated Construction of Steel–Concrete Composite Bridges

Various methods have been developed to produce deck slabs for steel–concrete composite bridges. Usually, the deck slabs are cast with in situ concrete using a formwork carriage, resulting in construction progress of 15 to 25 m of deck slab per week. A new construction method was developed at the Institute of Structural Engineering (TU Wien), which enables the swift erection of the concrete deck slab. This method employs precast deck slab elements with reinforced concrete cross-beams which span in the transverse direction. With this new construction method, producing up to two deck slab sections of 15–25 m per day becomes possible. Further, the performance of novel reinforcement detailing required for the precast deck slab elements is investigated by structural testing. The experiments consist of eight load-bearing tests on four specimens which represent sections of the element during casting and after completion. The investigated parameters in series 1 are the length and spacing of loops, used for protruding longitudinal bars enclosure. In series 2, the enclosure of the shear reinforcement and the height of the cross beams are varied. The results show that the targeted bending capacity could be reached in all tests with no signs of premature failure due to detailing reasons. Based on the experimental results, the feasibility of the new approach is shown and recommendations for detailing are given.

Vibration Control of the Steel-Concrete Composite Box Girder Bridge with Slip and Shear-Lag Effects by MTMDs under the Train-Bridge Interaction

Steel-concrete composite girder bridges, in essence, are thin-walled structures, the dynamic responses of which will be greater than those of a typical Euler–Bernoulli beam under the train-bridge interaction because of the shear lag and interface slip. Thus, in this study, the dynamic analysis model of a train-composite box girder bridge-multiple tuned mass damper (MTMD) coupling system is proposed, with the derived dynamic equations of this time-varying system. Meanwhile, the program is compiled using the Newmark-β method for the solution, combined with the optimization toolbox to solve the complex optimization design problems of MTMDs involved. Finally, factors affecting the vibration-damping effect are studied, such as the mass ratio of MTMDs, the number of trains, and the slip and shear lag of the composite box girder bridge.

RBF-PSO-IS: An innovative metamodeling for reliability analysis of bridge's vortex-induced vibration

The complexity of vortex-induced vibration (VIV) instability analysis originates from the variability of the wind environment, the randomness of the analytical model, the ambiguity of the failure criterion, and the high-dimensional nonlinearity and non-explicitness nature of the instability function. This paper addresses the low sampling efficiency and challenges in approximating failure probability in prior research on reliability. By integrating an adaptive sampling strategy with particle swarm optimization (PSO), an initial VIV reliability metamodel is established, which is subsequently resampled to create a more refined metamodel. A combination of multiple reliability algorithms is then employed to calculate the maximum amplitude of VIV and the failure probability of the VIV interval. The validity and accuracy of the proposed method are demonstrated through two representative numerical examples. The results indicate that the proposed radial basis function (RBF)-PSO-importance sampling (IS) analysis method and its adaptive random sampling strategy can significantly reduce the computational cost associated with extensive finite element model operations and the complexity arising from the high-dimensional nonlinearity and non-significance of the limit state function (LSF). This method enables researchers to achieve more accurate and time-saving solutions for VIV in steel–concrete composite bridges.

Investigations on influences of Engineered Cementitious Composites (ECC) on pull-out properties of studs in steel-concrete composite bridge

Stud plays an important role in the connection of steel-concrete composite bridge (SCCB). The stud is under pull-out load in the negative moment zone of SCCB. Engineered Cementitious Composites (ECC) are a new type of materials with tensile strain hardening and multiple cracking behavior to strengthen SCCBs. In this study, the cyclic pull-out effect on the ECC-stud connection was studied through pull-out tests. The stud diameter (d=13/16 mm) and the embedment depth (hef=40/60/80 mm) are included as design parameters, resulting in a total of 18 specimens of six scenarios. The failure mode, load-bearing capacity, and ductility factor of the specimens under cyclic loading are compared with those under monotonic loading, and the stiffness, energy dissipation capacity, and residual displacement of the specimens under cyclic loading are analyzed. Based on the experimental results, under cyclic loading, the concrete cone failure and splitting failure occur, and the threshold of hef/d between the two failure modes is 3.75–4.62, which is smaller than the threshold of the monotonic scenarios. Both concrete and splitting failure modes show ductile failure characteristics because of the bridging effect of fibers in ECC. The load-bearing capacity and ductility factor under cyclic loading are lower than those under monotonic load. This is because, under cyclic loading, the specimens show cumulative damage, which, however, is weakened due to the strengthening effect of ECC. As d and hef increase, the load-bearing capacity, ductility factor, stiffness, and energy dissipation capacity increase correspondingly, and the residual displacement decreases. The stud with a larger d shows a more obvious ductility holding stage.

Experimental research on curved continuous steel-concrete composite twin I-girder bridge

Due to the excellent economy and convenient erection, curved continuous steel–concrete composite twin I-girder (CTIG) bridges have been applied in mountainous bridges and unban overpasses. Rigorous investigation of the bending-torsion interaction is important for the curved continuous CTIG bridge design. A CTIG model bridge with a span arrangement of 17.46 m + 17.46 m and a curved radius of 200 m, was fabricated and tested under a symmetric static load. The mechanical behavior and failure modes of the model bridge were investigated. Results show that the non-uniform torsion and the web distortion effect are the characteristic mechanical behaviours of the curved CTIG bridge. The crossbeams resist the web distortion to ensure the transmission of the torsional moment. The constraint of the web distortion by the crossbeams results in the bottom flanges of the CTIG bridge being subjected to additional lateral bending moments. The ultimate strength of the CTIG bridge studied in this research is reached by a shear failure involving web buckling, formation of diagonal web yielding, and concrete deck crushing. This study contributes to a deeper understanding of the mechanical behavior of the curved continuous CTIG bridge and provides a valuable experimental basis for research regarding the design of bridges of this type.

Fatigue test study of weathering steel-concrete composite beam under corrosive environment

In this paper, two sets of comparative fatigue tests on weathering steel-concrete composite girders were carried out in the context of steel-concrete composite girder bridges. The load-deflection relationship of the weathering steel-concrete composite girders under fatigue loading in different environments was investigated contrastively. The experimental results show that under the coupled effect of corrosive environment and fatigue load, the weathering steel still shows obvious corrosion; the simple fatigue load has no significant effect on the stiffness and fatigue modulus of the weathering steel-concrete composite beam, while the coupled effect of corrosive environment and fatigue has a significant weakening effect on the stiffness of the beam, and the weakening of concrete is apparently greater than that of steel beam.

Numerical Investigation on Novel Shear Connectors in Prefabricated Composite Beams

An innovative horizontal-arranged shear stud was proposed for prefabricated composite beams, in response to the engineering demand for accelerated precast decks construction on steel–concrete composite bridges. In order to verify the shear behavior of the studs, a push-out test was performed in which two groups of specimens were designed, and each group included three specimens. In addition, a finite element method based on the ABAQUS2020 software was adopted to analyze the influence factors of the prefabricated studs, which reveals the most influential factor, to provide a guide for optimum design. Therefore, 10 models were established, including one finite element model with the same parameters as the push-out test, and 9 models based on an orthogonal testing design. The results showed that, firstly, the prefabricated shear studs had longitudinal shear resistance, the same as conventional shear studs. Secondly, the ultimate load capacity, as well as the ductility of the prefabricated studs, was better than conventional studs. Thirdly, the modeling results were in good agreement with the push-out test results, which indicated the validity of the modeling method. Lastly, by analyzing the calculated results of the nine orthogonal models, it was found that the stud diameter was the most influential factor for the shear capacity, and the shear capacity was directly proportional to the stud diameter, while it was not proportional to the other factors. This study is evidence that the orthogonal testing design has a high efficiency in finite element modeling, which will provide a guide for the optimum design of prefabricated shear studs.

Experimental investigation on mechanical behavior of T-type perfobond rid shear connectors under combined shear and tension

The stress of shear connectors becomes more complicated as the span length of steel-concrete composite bridges increases. To bear the great shear and uplift forces, a T-type perfobond rib (T-type PBL) shear connector with sufficient stiffness and ductility is proposed. While the shear behavior of T-type PBL connectors has been evaluated in previous studies, its mechanical performance under combined shear and tension is not well understood due to the particular shape and numerous impact factors. Therefore, one pull-out test considering pure tension and seven modified push-out tests considering combined shear and tension were carried out to investigate the failure mode, bearing capacity, and load-slip behavior of T-type PBL connectors under combined actions. The pull-out test was performed to determine the tensile resistance, followed by a series of modified push-out tests with constant horizontal tension to investigate the structural behaviors. Additionally, the effects of the rib height, flange width, and hole numbers were evaluated. Based on the test results, conical failure surfaces formed from the flange of the T-type PBL to the concrete surface for all specimens, and the concrete failure angle was approximately 32°. The bearing capacity of the specimen improved by 26% when the perfobond rib height increased from 100 mm to 120 mm, but the flange width barely had any effect. The capacity of 1-hole specimen dropped by 20% while 2-hole specimen increased by 8% compared to the standard specimen, which may relate to the distance between adjacent holes. Increasing the rib height by 25% and 50% reduced the initial relative slip (S90) by 30% and 32%, respectively, indicating the improvement in initial stiffness. Generally, the pull-out resistance of the T-type PBL shear connector was enhanced by increasing the flange width, rib height, and number of holes. An evaluation equation considering the hole number and hole spacing was suggested for the bearing capacity of T-type PBL shear connectors under the combined actions. The validity was verified by test results, with a calculated-to-test-result ratio of 1.12 and standard deviation of 0.15. This study could enhance the understanding of the behavior of T-type PBL connectors under the combined actions, and promote the potential application in long-span composite bridge decks.

An efficient model for solar radiation induced top displacement of steel-concrete composite bridge towers

The temperature effect caused by solar radiation significantly influences the stress state of bridges. Especially for ultra-high bridge towers, considerable deformation induced by solar radiation affects the safety of the structures. This research is conducted to evaluate the temperature deformation of a steel–concrete composite bridge tower where a sliding saddle is adopted. First, the temperature distribution pattern of the structure is analyzed. Second, based on the temperature distribution, an efficient model which can be applied to the long-term calculation is established, aiming at directly calculating the deformation results. Then, an outdoor experiment study is carried out to verify the temperature distribution and the results of sectional curvature. Finally, the efficient model is applied to calculate the annual bidirectional deformation. This method realizes the long-term temperature effect evaluation of the structure before construction, and the results can be referred to as guidance for the analysis of related types of structures.

Study on Temperature Effect and Calculation Method of Steel-Concrete Composite Bridge

In order to investigate the mechanical performance of the steel-concrete composite beam bridge under temperature, the stress and shear distribution of the three-span composite continuous beam bridge under temperature are investigated by combining finite element and theoretical methods. The results show that the maximum error ratios of the longitudinal stress obtained by the two calculation methods are 8.7% and 9.4% under the system temperature and temperature gradient, respectively. The maximum errors of the stress curves are less than 5%, which is in the acceptable range. The reasonableness of the finite element calculation results is proved and a basis for the mechanical performance analysis of the combined continuous girder under temperature is provided.

Full-scale push-out testing of headed stud-steel block connectors in prefabricated steel-concrete composite beams

Full-scale push-out tests of 13specimens were conducted to study the shear behavior of the headed stud-steel block connectors (HSBCs) in prefabricated steel-concrete composite bridge beams, where the key parameters of steel block height, longitudinal connector spacing, presence of oblique rebars in the precast slab, and grouting material were considered. The objective was to develop large shear stiffness, high shear capacity, and sufficient deformability of the connectors in prefabricated steel-concrete composite bridge beams. The results from the push-out tests reveal: two main failure modes the compression failure in the concrete slab and the shear failure in the grouting material and concrete slab; and the HSBC has large shear stiffness, high shear capacity (≈1500kN), and sufficient deformability. Based on the analysis of the shear extrusion dimension of the grouting material and concrete slab, the shear inclination ratio was found approximately to be 1:5, which agrees well with the stipulation specified in the EC4. The height and spacing of HSBCs are the two principal parameters affecting the shear capacity and failure mode of the specimens. By comparing the measured shear capacities of the HSBCs with those calculated by the design formulas for steel blocks and headed studs as specified in the EC4, it is shown that the steel block and headed studs can work together to resist the force between the precast concrete slab and the steel beam.