Steel-concrete Composite Box Girder Research Articles

Study on Vibration and Noise of Railway Steel–Concrete Composite Box Girder Bridge Considering Vehicle–Bridge Coupling Effect

A steel–concrete composite beam bridge fully exploits the mechanical advantages of the concrete structure and steel structure, and has the advantages of a fast construction speed and large stiffness. It is of certain research value to explore the application of this bridge type in the field of railway bridges. However, with the rapid development of domestic high-speed railway construction, the problem of vibration and noise radiation of high-speed railway bridges caused by train loads is becoming more and more serious. A steel–concrete composite beam bridge combines the tensile characteristics of steel and the compressive characteristics of concrete perfectly. At the same time, it also has the characteristics of a steel bridge and concrete bridge in terms of vibration and noise radiation. This feature makes the study of the vibration and noise of the bridge type more complicated. Therefore, in this paper, the characteristics of vibration and noise radiation of a high-speed railway steel–concrete composite box girder bridge are studied in detail from two aspects: the theoretical basis and a numerical simulation. The main results obtained are as follows: Relying on the idea of vehicle–rail–bridge coupling dynamics, a structural dynamics analysis model of a steel–concrete combined girder bridge for a high-speed railroad was established, and numerical program simulation of the vibration of the vehicle–rail–bridge coupling system was carried out based on the parametric design language of ANSYS 18.0 and the language of MATLAB R2021a, and the structural vibration results were analyzed in both the time domain and frequency domain. By using different time-step loading for the vehicle–rail–bridge coupling vibration analysis, the computational efficiency can be effectively improved under the condition of guaranteeing the accuracy of the result analysis within 100 Hz. Based on the power flow equilibrium equation, a statistical energy method of calculating the high-frequency noise radiation is theoretically derived. Based on the theoretical basis of the statistical energy method, the high-frequency noise in the structure is numerically simulated in the VAONE 2021 software, and the average contribution of the concrete roof plate to the three acoustic field points constructed in this paper is as high as 50%, which is of great significance in the study of noise reduction in steel–concrete composite girders.

Fatigue performance of stud connectors in joints between top slabs and steel girders with corrugated webs subjected to transverse bending moments

Steel-concrete composite box girders with corrugated steel webs (CSWs) are broadly used in bridge engineering, in which the joints between top RC slabs and steel girders with CSWs are usually subjected to transverse bending moments caused by off-center vehicle loads. Stud connectors arranged in the joints usually bear repeated pull-out forces in this case and are prone to fatigue failure. Therefore, two reduced scale joints between top slabs and weathering steel girders with CSWs were designed and tested, on which variable amplitude fatigue loads were applied to investigate the fatigue performance of studs incorporated in the joints. The two joints presented similar fatigue behavior, i.e., cracks of not more than 0.26 mm in width appeared on the surface of the top slab during the fatigue loading, and the separation of the top RC slabs and the top girder flanges was observed; meanwhile, minute cracks developed along the welds connecting the CSW with the bottom girder flange, and the stiffness of the joints gradually decreased due to the accumulation of fatigue damage. The two joints underwent 2,650,000 and 2,103,600 load cycles respectively before fatigue failure occurred. After partially demolishing the RC slabs, several welded head studs in the joints were observed fractured at the roots and detached from the top girder flange. Whereafter, finite element (FE) models referring to the test joints were developed and analyzed, and the effect of the wave height (WH) of the CSW and the transverse row spacing (TRS) of studs on the distribution of pull-out forces among studs was investigated. It showed that the pull-out force bore by each stud in the joint was distributed unevenly even in the same row. Then, a modification factor α was introduced to revise the pull-out forces of studs calculated in the theoretical method. An equation to determine the factor was fitted, considering the effect of the WH of the CSW and the TRS of studs. Finally, the detail category for studs bearing pull-out forces in the joints was discussed based on the experimental results and the collected test data, and it was preliminarily recommended studs subjected to pull-out forces can be classified into detail category 45 specified by Eurocode 3 in fatigue design.

Effective width of steel-concrete composite box girder bridges: a review and method comparison

Steel-concrete composite girders have non-uniform stress distribution on the slab, presenting maximum stresses next to the webs of the girder. This phenomenon is known as shear lag effect. To understand this effect, there is the effective width concept, in which only a portion of the slab width is considered effective in contributing to the composite element’s resistant capacity. However, in the technical standards, there is no recommendation for calculating the effective width in steel-concrete composite box girder bridges. In view of this situation, the purpose of this paper is to carry out a systematic review on effective width and/or the shear lag effect in steel-concrete composite bridges, in order to raise the main existing recommendations and compare them. Through a bibliometric scan with carefully chosen keywords, it was found that of all research on shear lag or effective width in steel-concrete composite structures, only 31.19 are on bridges and 14.97% are on bridges with box girders. Among the papers, those that have a method for calculating the effective width of steel-concrete composite girder bridges have been compared quantitatively and qualitatively with the procedures of AASHTO and EN 1994-2-2. In these procedures were also identified that the, for the boundary conditions of the present paper, the parameters that most influencing the effective width are, in that order, the span length, the distance between girders, the concrete slab height, the longitudinal position and the type of load.

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.

Experimental Study and Theoretical Analysis of Steel–Concrete Composite Box Girder Bending Moment–Curvature Restoring Force

A steel–concrete composite box girder has good anti-seismic energy dissipation capacity, absorbs seismic energy, and reduces seismic action. It is very suitable for high-rise and super high-rise mega composite structure systems, which is in accordance with the condition of capital construction. In order to accurately study the elastic–plastic seismic response of the composite structure, the restoring force model of the building structure is the primary problem that needs to be solved. Previous research shows that shear connection degree, force ratio, and web height–thickness ratio are the major factors that influence composite box girder bearing capacity and seismic behavior. In this paper, low cycle vertical load tests of four steel–concrete composite box girders were conducted with different shear connection degrees and ratios of web height to thickness. The seismic behavior of a steel–concrete composite box girder was analyzed in depth, such as the hysteresis law, skeleton curve, and stiffness degradation law, etc. The influence of the shear connection degree and ratio of web height to thickness on seismic performance of the steel–concrete composite box girder was investigated. A three-fold line model of the bending moment–curvature skeleton curve of composite box girders was established. On the basis of experimental data and theoretical analysis, the formula of positive and negative stiffness degradation of composite box girders was obtained. Furthermore, the maximum point orientation hysteresis model of the bending moment–curvature of steel–concrete composite box girders was established. The calculated results of the restoring force model agree well with the experimental results. The accuracy of the proposed method is verified. The calculation method of the model is simple and clear, convenient for hand calculation, and suitable for engineering applications.

Improved-GEP-based models for predicting distortion control indices of curved composite box girders

Curved steel-concrete composite box girders are subjected to complex torsional actions under vertical loads, which may generate excessive distortional warping stresses. However, the complexity of the distortional warping stresses makes it challenging to obtain a quantitative prediction method, which may result in the adoption of potentially unsafe or uneconomical diaphragm designs. In this paper, improved-GEP (gene expression programming)-based models for predicting two distortion control indices of curved composite girder bridges are proposed. The key parameters in distortion equation for the curved composite box girder bridges are derived first, and then a comprehensive parametric analysis is conducted. Subsequently, an improved GEP algorithm is proposed to establish the formulas for calculating two distortion control indices. Compared to the traditional GEP, the proposed algorithm can markedly improve the mining ability of the constant terms and coefficients and enhance the global search ability by introducing a least squares algorithm and a new-generation and quasi-offspring mixed competitive strategy. In addition, with the operative and terminal symbols determined based on distortion theory, the efficiency and physical significance of the GEP models are effectively enhanced. The statistical indices and sensitivity analysis demonstrate that the proposed models for predicting the two distortion control indices agree with the finite element analysis results and distortion theory.

Time-varying solar radiation-induced non-uniform temperature distribution of steel-concrete composite box girder-ballastless track system

Aiming to investigate the non-uniform temperature distribution of the steel-concrete composite box girder-ballastless track system induced by the time-varying solar radiation, the ray-tracing algorithm was used to calculate the environmental parameters. The segment finite element model (SFEM) for spatial interaction between the bridge and the ballastless track was used to perform several numerical simulations. The temperature variation induced by solar radiation was evaluated based on the numerical simulations. The results showed that the peak temperature of the system (on the western side of the steel web) was 49.59 Co (at 16:00). Regarding time-varying solar temperature distribution of the steel-concrete composite box girder-ballastless track system, a difference was found between the western and eastern sides of the steel webs. Finally, the vertical temperature gradient model of the steel-concrete composite box girder-ballastless track system was established according to the most unfavorable temperature. The results provided a reference for constructing and maintaining a steel-concrete composite box girder equipped with the ballastless track.

Effects of installing concrete deck on noise radiation of steel box girders: Mechanisms, modeling, and analysis of influential factors

Steel–concrete composite box girder (SCC BG) is widely used in engineering because it can make full use of the tensile properties of steel and the compressive properties of concrete. However, research on the vibrational transmission and vibroacoustic response of the SCC BG is still relatively rare. In this study, a laboratory hammering test was performed to obtain the dynamic characteristics of a scaled specimen of an SCC BG before and after installing a concrete deck. The experimental results revealed that the vibroacoustic response was greatly reduced after the installation of concrete deck due to a reduction in the transmission of on-deck vibrations to the steel box girder. Following this, we introduce a model to predict the structural vibroacoustic response of the SCC BG based on the hybrid finite element–boundary element–statistical energy analysis method, and verify its accuracy through experiments. The accurately calibrated model is then used to study the characteristics of vibration transmission between plates of the SCC BG. The influences of the thickness of the concrete deck, concrete material, and degree of shear connection on vibroacoustic responses of the SCC BG are also discussed.

Experiment Analysis on Crack Resistance in Negative Moment Zone of Steel–Concrete Composite Continuous Girder Improved by Interfacial Slip

Due to the strong interface effect of continuous steel-concrete composite beams with conventional shear connectors, the efficiency of applying pre-stress in the negative moment zone is greatly reduced, which leads to a difficulty of anti-cracking design in the negative moment zone of pre-stressed steel-concrete composite box girder. In order to study the feasibility and the working mechanism of improving the crack resistance of continuous steel-concrete composite bridges by releasing the interfacial slip effect within the negative bending moment region, two groups of model tests were carried out in the paper. Two steel-concrete composite beams were used for model test, one of them using the conventional stud shear connectors, another one using the new shear connectors, named uplift-restricted and slip-permitted shear connectors. The results show that, compared with the composite beam with conventional shear studs, the composite beams with uplift-restricted and slip-permitted shear connectors have a higher pre-stress application efficiency, and the new connector could release the interface slip, which can make the tensile stress distribution in concrete slab more uniform within the negative moment zone, thus increasing the cracking load of concrete slab and reducing the subsequent crack width effectively. This study is helpful to understand the relationship between the interface slip and the anti-crack characteristics in negative moment zones, and a new anti-crack design method is proposed for the design of continuous composite girder.

Experimental and numerical study on vibration and structure-borne noise of composite box-girder railway bridges

ABSTRACT This paper adopts a proficient approach to evaluate vibration and structure-borne noise and makes up for the steel-concrete composite (SCC) box girder vacancy in the SCC structure. First, the dynamic equation of the train-rail system is established, the pseudo-response of the system in the frequency domain is appropriately assessed by pseudo excitation method (PEM), and the frequency spectra of the wheel-rail force as well as the forces transmitted to the bridge are obtained. Next, applying the force to the finite element method (FEM), boundary element method (BEM), and statistical energy analysis (SEA) model. The vibration and structure-borne noise of the SCC box girder are calculated in the frequency domain. Then, the effectiveness of the method and model is verified through the comparison of the field experimental results. Finally, the effect of the ground reflection in the SEA model is considered using the sound ray-tracing method for the first time.

Mechanical performance based rationalization research on steel-concrete double composite action

Casting an extra concrete bottom layer to a steel-concrete composite box girder in a hogging moment region can increase sectional stiffness and prevent steel buckling. However, a lower sectional neutral axis may not be favorable to concrete slab cracking and steel flange stress control. To this end, a double composite girder segment was proposed and investigated. Particularly, a static loading test on a large-scaled two-span continuous girder specimen with the double composite action in hogging moment region was conducted for mechanical investigation. Meanwhile, parametric analysis was carried out as well for a rational design scheme of the double composite section. The test results revealed that the load-carrying capacity of double composite section could be increased due to the contribution of extra bottom concrete layer. The transverse deformation of steel parts was favorably constraint. The parametric analysis results indicated that slab thickness that was 15% of steel girder height could provide most obvious contributions to the improvements of both sectional load-carrying capacity and cracking moment. Due to the additional reinforcement, the steel web thickness of double composite girder can be saved 16.7% and the steel bottom flange thickness only needs to meet the constructing requirement compared with common composite girder. Besides, the analysis also showed replacing the tub section with steel box section in the hogging moment region can reduce the stress on top flange by 24.4%. These results are an important basis for establishing a rational design scheme for the novel double composite section.

Social Impact Assessment Comparison of Composite and Concrete Bridge Alternatives

The definition of sustainability includes three fundamental pillars: economic, environmental, and social. Studies of the economic impact on civil engineering infrastructures have been focused on cost reduction. It is not necessarily in line with economic sustainability due to the lack of other economic factors. Moreover, the social pillar assessment has been weakly developed compared to the economic and the environmental ones. It is essential to focus on the social pillar and evaluate clear indicators that allow researchers to compare alternatives. Furthermore, bridge life cycle assessment studies have been focused on concrete options. This has resulted in a lack of analysis of the impact of composite bridge alternatives. This study is conducted in two stages. The first part of the study makes a cradle-to-grave social and environmental sustainability evaluation with the SOCA v2 and ecoinvent v3.7.1 databases. This assessment is carried out on four concrete and composite bridge alternatives with span lengths between 15 and 40 m. The social impact weighting method and recipe have been used to obtain the social and environmental indicators. The second part of the study compares the results obtained from the social and environmental assessment of the concrete and the composite alternatives varying the steel recycling rate. The bridge alternatives are prestressed concrete solid slab, prestressed concrete lightened slab, prestressed concrete box-girder, and steel–concrete composite box-girder. The results show that composite options are the best for environmental impact, but the concrete box girder solutions are better for social impact. Furthermore, an increase in the steel recycling rate increases the social impact and decreases the environmental one.

Prediction model for load effective distribution width of slab in composite box girders using gene expression programming

To determine the loading condition of the deck slab in girder bridges, the concept of the load effective distribution width is widely accepted in practical design. However, effective models for calculating the load effective distribution width of deck slab in steel–concrete composite box girders (SCCBG) are still lacking, which may bring about significant errors in slab design. In this study, a rational model to calculate the load effective distribution width of deck slabs in SCCBG in both the elastic and elastoplastic stages is proposed using the gene expression programming (GEP). First, four loading tests were conducted and elaborate finite element (FE) models were developed to investigate the load distribution of the slab in SCCBG. The FE models were validated by the test results and then applied to conduct a comprehensive parametric study to obtain the influences of the design parameters and the database for the GEP model. On this basis, formulas forthe load effective distributionwidth in the elastic and elastoplastic stages were proposed by using the GEP algorithm. Furthermore, extra testing data were applied to verify the validity of the proposed models. By comparing the results given by several bridge codes, it is demonstrated that the proposed models can provide more accurate and reliable predictions and are quite simple and useful for pre-design applications.

Slip analysis of prestressed steel-concrete continuous composite beam

To analyze the horizontal shear resistance participation degree of the shear studs on the web and diaphragm flange in the negative moment area of the steel–concrete continuous composite box girder, the steel–concrete composite girder specimen was designed and manufactured based on the existing codes. The shear deformation of the two parts of the studs in the composite box girder is studied by the finite element parameter analysis of the nonlinear shear deformation of the studs and the stress analysis of the diaphragm. The results show that web flange studs provide the horizontal shear capacity of the steel–concrete composite box girder. The installation of baffle flange studs cannot improve the shear connection degree of composite beams. Removal of the flange stud from the diaphragm can relieve the force on the diaphragm and provide a theoretical basis for reducing the stiffeners of the diaphragm.

Parameter and sensitivity reliability analysis of curved composite box beam

Aiming at the reliability problem of curved steel-concrete composite box girder, this article adopts the research methods of numerical simulation and model test. A load–slip constitutive relationship suitable for simulating composite box girder shear connectors is proposed, which is introduced into ANSYS finite element program and a three-dimensional finite element analysis model is established. At the same time, a model test is established for verification. The comparison between the results of numerical simulation and model experiment verifies the correctness and applicability of the finite element analysis model. According to the mechanical characteristics of the curved steel-concrete composite box girder, the influence of different design parameters on the load-bearing capacity of the curved composite box girder bridge is studied. Based on the sensitivity index, the influence degree of the design parameters on the structural reliability of the curved composite box girder is judged. The influence of the sensitivity of the design parameters of the curved steel-concrete composite box girder bridge on the flexural reliability of the structure is discussed. The optimal measures to improve the flexural bearing capacity of curved steel-concrete composite beam bridges are proposed. It is expected to provide new ideas and analysis methods for the optimization design and reliability analysis of curved composite box girder.

Lateral overturning process and failure mechanism of curved steel-concrete composite box-girder bridges under specific overloading vehicles

Curved steel–concrete composite girders are regularly adopted for use in ramp bridges in urban overpasses. As such, it is important that the lateral overturning stability of girders supported by single-column piers is analyzed. In order to comprehensively evaluate the lateral overturning mechanism of girders, this paper carries out a full-range nonlinear analysis of the lateral overturning process of a three-span curved steel–concrete composite box girder based on the explicit dynamic finite element (FE) method. According to the FE analysis results and actual forces acting on the structure, a new method for analyzing overturning stability considering the corresponding limit state is proposed. The results show that the overturning process can be divided into three stages: (i) small girder rotation; (ii) large girder rotation; and (iii) lateral displacement and overturning. The mechanical behaviors, overturning processes and failure characteristics of curved steel–concrete composite girders are similar to those of typical concrete box girders. However, some distinct characteristics, including the crawling behavior of girders and buckling of bottom plates, only exist in composite girders. The proposed overturning stability checking method is found to be more appropriate for determining the bearing capacity of girders on the ultimate limit state than the current design method described in the specifications (JTG 3362-2018). Some measures – such as setting lateral movement limiting devices, setting pre-eccentricity of supports and increasing the distance between supports which can considerably improve the lateral overturning stability of steel–concrete composite girders – are highlighted.

Distortion of steel tub-girder with top flange bracing considering warping restraint effect

During the construction stage of the steel-concrete composite box girder, the steel tub-girder has to support its weight, the self-weight of the wet concrete, and other construction loads. To improve the torsional stiffness of the steel tub-girder, the top flange bracing is often used to connect the top flanges to make “semi-closed” cross sections. The steel tub-girder with top flange bracing can form a closed shear flow under torsion, and thereby causing the distortion effect. However, the distortional behavior of this type of structure remains unclear. In this paper, the equivalent thickness of the fictitious top flange is first derived based on the restrained torsion theory. Subsequently, the errors of distortion loads given by the conventional load decomposition method which ignores the effect of warping restraint are derived, and are further verified by finite element analysis. It is demonstrated that the effect of warping restraint on the distortion is significant in the continuous tub-girder bridges with the top flange bracing. Therefore, the corresponding correction coefficients for the distortion loads caused by eccentric vertical loads and the girder axis curvature are proposed, and the simplified formulas for estimating these correction coefficients are established based on parametric analyses. Finally, the calculation method for the internal force of cross frames is modified and the accuracy of the proposed method is validated with results from finite element analysis.

Stressing state analysis of multi-span continuous steel-concrete composite box girder

This paper uses the theory of structural stressing state to study the working characteristics of three multi-span continuous steel-concrete composite box girder (SCCBG) models with different prestress levels. Firstly, the generalized strain energy density (GSED) is constructed to reveal the working state of the structure based on the experimental strain data, the Mann-Kendall (M-K) criterion is applied to distinguish the leap characteristics load points (P and Q) of the structural stressing state and defined as the “failure load”. It is used to update the existing structural “destruction” load to more clearly reflect the entire structural failure process. Then, the working state parameters of the cross-section are described (strain distribution mode, midspan deflection, crack width, etc.) to analyze the working behavior of the box girder model. Finally, the non-sample point interpolation method (NPI) is used to reasonably expand the experimental strain data, to verify the rationality of the characteristic load points, and the stressing state characteristics of box girders with different prestressed levels are further discussed.

Fatigue Performance of Steel-Concrete Composite Continuous Box Girder Bridge Deck

The fatigue performance of the bridge deck significantly affects the safety and durability of the overall steel-concrete composite beam bridge. Based on the vehicle flow information of the highway within 10 years, the fatigue performance of a two-way four-lane steel-concrete composite continuous beam bridge deck is studied in this research. The results indicate that the effect of the wheel track position is negligible for two-way four-lane bridge when the wheel track sways laterally, and the fatigue stress of bridge deck concrete is the most unfavorable while the loading position is 7.0 m away from the bridge center line. The fatigue damage decreases by 30%–40% when the centerline of the lane deviates from the most unfavorable stress position by 1 m. The punching fatigue of the concrete is more sensitive to the changes in slab thickness, and the thickness of the deck concrete slab is recommended to be ≥35 cm.

Numerical analysis on the time-varying temperature field distribution patterns of ballastless track steel-concrete composite box girders at ambient temperature based on field measurements

To analyze the time-varying temperature field distribution pattern of ballastless track steel-concrete composite box girders for a high-speed railway at ambient temperature, a numerical model for analyzing the time-varying temperature field of steel-concrete composite box girders was established based on the long-term monitoring data for the internal and external environments of the main girder of the Ganjiang Bridge on the Nanchang-Ganzhou high-speed railway. The influence of factors such as the deck pavement and the ambient wind speed on the time-varying temperature field of the steel-concrete composite box girders were considered. The results showed that there was a significant difference in the vertical temperature gradient patterns on sections at the side web and at the middle web at the same moment in time due to the hindering effect of the track board on the heat exchange between the ambient temperature and the main girder. Increasing the wind speed accelerated the rate of heat exchange between the main girder surface and the environment. In particular, when the internal temperature of the girder was higher than the ambient temperature, the higher the wind speed was, the larger the temperature gradient was. This study lays a foundation for accurate analysis of the structural response of ballastless track steel-concrete composite girder bridges at ambient temperature.