Composite Box Girder Research Articles

Exact distortional behaviour of single-box multicell curved composite box girders with corrugated steel webs in the elastic stage

The distortional effect in a curved composite box girder with corrugated steel webs (CCBG-CSWs) generated by the combined action of an eccentric load and axis curvature is apparent owing to the thin steel web. The distortional effect in a single-box girder with multicell cross-section is more complex than that with a single-cell cross-section; this is owing to the various distortion modes, which can be classified into first and second distortions. Herein, analytical solutions for both the first and second distortional effects, as well as for the case with diaphragms, were derived based on the energy variational principle and solved using the beam on elastic foundation (B.E.F.) analogy for single-box, multicell, and simply-supported CCBG-CSWs in the elastic stage. Experiments and finite element analyses were performed to validate the analytical solutions. The ratios of the first to second distortional angle (stress) were approximately 2:1 (5.25:1) and 2.8:1 (8:1) for the double-cell and triple-cell sections, respectively, indicating that the second distortional effect cannot be ignored for the single-box multicell CCBG-CSWs. A parametric study regarding the diaphragm number, span–radius ratio, and span demonstrates that the distortional stress ratio (ratio of the summation of the first and second distortional normal stresses to the flexural normal stress) exponentially decreases as the diaphragm number and span increase, and linearly increases as the span–radius ratio increases, however, when the diaphragm number is sufficient, the distortional stress ratio is considered almost constant. Based on the parametric study, a practical equation considering both the first and second distortions was proposed using the regression analysis method to predict the diaphragm space of multicell CCBG-CSWs with the desired distortional stress ratio as the control index.

The Effect of Interior Stiffeners on the Flexural Behavior of Concrete-Filled Steel Tube Composite Box Girders

The composite box girder is a structural element with high torsional stiffness and resistance against flexural loads. A new form of bridge construction is the Concrete-Filled Steel Tubes (CFSTs) linked to composite slabs by steel trusses. In this study, four different kinds of composite box girders linked to steel tubes filled with concrete were analyzed experimentally and numerically while being subjected to flexural loads. The specimens were evaluated when subjected to a focused load at the mid-span. The first model is a concrete-filled tube without stiffeners and was considered the control specimen, the second model is a concrete-filled tube with internal I–shaped stiffeners welded inside the steel tube, the third was filled with T-shaped stiffeners, and the fourth with V-shaped stiffeners. The test results showed that the CFST sections with interior stiffeners gave higher strength capacity and less deflection than the control specimen. The best shape of the stiffeners was the T-shape. The numerical analysis results were in accordance with the test results.

Research on Reasonable Construction Plan for Cast-in-Place UHPC Bridge Deck Plate of Cable-Stayed Bridge

This article takes a single-tower cable-stayed bridge with a steel-UHPC composite deck steel box girder as the research object and develops different casting plans for the UHPC layer on the bridge deck. It analyzes the influence of factors such as the block casting sequence of the UHPC layer on the bridge deck, whether or not to set up a post-casting section, whether or not to set up bridge deck counterweights and the range of it on the additional deformation and stress of the formed UHPC bridge deck during the construction stage, exploring the impact of various factors on the structural target bridge’s completion status (cable force, bridge completion linearity, bridge deck and steel box girder stress) under different pouring schemes. Research has shown that under the constant initial tension of stay cables, adjusting the pouring sequence of UHPC bridge decks and setting post-pouring sections is not significant in reducing the tensile stress of UHPC bridge decks. The more effective technical measure is to use bridge deck counterweight pouring during construction; the closer the counterweight is to the later stage constant load loading value, the more significant the decrease in UHPC tensile stress is. When factors such as on-site construction conditions, construction period, and labor costs are limited, local weight balancing on the bridge deck can be used.

Experimental Study on the Flexural Behavior of a Novel Nonprismatic Prestressed UHPC Composite Box Girder with Corrugated Steel Webs

Experimental Study on the Flexural Behavior of a Novel Nonprismatic Prestressed UHPC Composite Box Girder with Corrugated Steel Webs

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.

Seismic Vulnerability Analysis of Long-Span Prestressed Concrete Composite Box Girder Bridge with Corrugated Steel Webs under Construction

In order to address the difficulty in determining the seismic damage probability of continuous girder bridges under construction, the seismic vulnerability analysis method of the construction state is proposed in this study. Firstly, taking a long-span prestressed concrete composite box girder bridge with corrugated steel webs (OSW) as an example, the finite element models (FEMs) of dynamic calculation in different phases of cantilever construction are simulated by OpenSEES. Secondly, by selecting reasonable seismic waves and seismic intensity measures, the non-linear time-history analysis is carried out, followed by the demand parameters and damage indexes suitable for the construction state proposed. Finally, the probabilistic seismic demand model (PSDA) of the continuous box girder bridge during the construction stage is constructed by using the “cloud method”, and the seismic vulnerability curves of the piers and temporary bearings are established to evaluate the seismic performance during the construction stage. The results indicate that the damage probability of piers and temporary bearings increases with the progress of construction. The initial formation of the cantilever structure and the sudden change in the size of the construction segmental girder correspond to a high probability of damage, and seismic protection measures should be strengthened during this construction state. Moreover, significantly higher damage probability of the components under construction compared to the completed bridge after it is built.

Comparison of the corrugated steel web composite box-girder and traditional girders regarding temperature field under solar radiation

The corrugated web composite box-girder (CWCB) is a novel structural form and has been widely adopted in bridge engineering due to its excellent mechanical properties and construction convenience. However, researches on the temperature field in CWCB is very limited, which may augment the risk of concrete cracking and steel web bucking and deteriorate the durability of bridge structures. This paper thereby experimentally investigates the time-varying and spatial temperature distribution features of CWCB based on a long-term temperature monitoring system. The experimental results indicate that the temperature field in CWCB is non-uniformly distributed and the vertical and horizontal temperature differences can reach up to 13.4 ℃ and 19.1 ℃, respectively. Meanwhile, the observed temperature distribution profile of the experimental CWCB is varying with seasons owing to the different exposure to solar radiation. Then, a refined numerical thermal simulation approach is developed and its reliability and accuracy have been validated by the experimental temperature data of three types of box-girders, i.e., CWCB, ordinary composite box-girder (OCB), and conventional concrete box-girder (CCB). Based on the validated numerical approach, the temperature fields of three full-sized box-girders are therewith compared and the results demonstrate that the temperature field in CWCB is much more complicated than the traditional box-girders. Besides, the obtained cross-sectional temperature differences of CWCB are significantly larger than that of the traditional box-girders. Finally, two temperature profiles have been proposed to characterize the thermal actions in CWCB, which are composed of parabolas and polylines. The outcome of this study can provide a useful tool for analyzing the temperature field and calculating the design thermal load of CWCB.

Full-Scale Fatigue Test and Finite Element Analysis on External Inclined Strut Welded Joints of a Wide-Flanged Composite Box Girder Bridge.

For a wide-flanged composite box girder bridge, the risk of fatigue cracking in the external inclined strut welded joint under the fatigue vehicle load is a problem. The main purposes of this research are to verify the safety of the main bridge of the Linyi Yellow River Bridge, a continuous composite box girder bridge, and to propose suggestions for optimization. In this research, a finite element model of one segment of the bridge was established to investigate the influence surface of the external inclined strut, and, using the nominal stress method, it was confirmed that the fatigue cracking of the welded details of the external inclined strut was risky. Subsequently, a full-scale fatigue test of the external inclined strut welded joint was carried out, and the crack propagation law and S-N curve of the welded details were obtained. Finally, a parametric analysis was conducted with the three-dimensional refined finite element models. The results showed that the welded joint in the real bridge has a fatigue life larger than that of the design life, and methods such as increasing the flange thickness of the external inclined strut and the diameter of the welding hole are beneficial to improve its fatigue performance.

Experimental and theoretical investigation of the shear lag effect in the novel non-prismatic prestressed CSW–UHPC composite box girders

Experimental and theoretical investigation of the shear lag effect in the novel non-prismatic prestressed CSW–UHPC composite box girders

Study on the Dynamic Response of Composite Box Girder Bridges with Corrugated Steel Webs

To more accurately consider the dynamic response of composite box girder bridges with corrugated steel webs under the effect of live loads, based on the theory of vehicle-bridge coupled vibration, a refined finite element model of vehicle-bridge coupled vibration analysis for composite box girders was established. The advanced dynamic response analysis of composite box girders with corrugated steel webs and traditional concrete box girders with 30 m single boxes and single cells, as well as with 50 m single boxes and multiple cells, was carried out. The research revealed that the natural vibration frequency of the composite box girder with corrugated steel webs is lower than that of the corresponding concrete box girder. When the bridge deck condition is poor, the dynamic impact coefficient of the composite box girder is much larger than that of the concrete box girder. When the bridge deck is in poor condition, the dynamic impact response is significantly enhanced, and the difference is significantly compared with that when the bridge deck is in good condition, which is greater than three times and even six times at the maximum. Both the difference in the vehicle model and the change in the vehicle speed influence the dynamic impact coefficient of the composite box girder.

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.

The Multi-Functional Modelling Shear Lag Method for Accurate Calculation of Static Response and Accordion Effect of Improved Composite Box Girders

The composite box girder with corrugated web and steel bottom plate (CW-SBS) is a kind of improved steel-concrete structures. The design of CW-SBS box girders needs the accurate method to calculate the working response and accordion effect in consideration of the self-stress equilibrium condition of shear lag warping stress and shear deformation. This study proposes the multi-functional modelling shear lag (MFMSL) method which adopts the four longitudinal displacement difference functions to model the variation of shear lag in the CW-SBS box girders with different wing slab widths and thicknesses. Therefore, MFMSL is a method to calculate the static response and accordion effect of the CW-SBS composite box girders. Structural differential equations based on the energy-variation principle present that the MFMSL method effectively improves the calculating accuracy of the CW-SBS box girder static response, which can be verified by both experimental and simulative results. Also, the MFMSL method demonstrates that the accordion effect of the CW-SBS box girder is stronger than that of the traditional composite box girder and closely relates to the load distribution. Hence, the proposed method further lays the foundation for the analysis and design of CW-SBS box girders.

Comparative Analysis of Composite Box Girder Bridges Using Beam on Elastic Foundation (BEF) Method, Space Frame Method, Finite Element Method and Computer Programming

Comparative Analysis of Composite Box Girder Bridges Using Beam on Elastic Foundation (BEF) Method, Space Frame Method, Finite Element Method and Computer Programming

Optimal Design of Segment Storage and Hoisting of Precast Segmental Composite Box Girders with Corrugated Steel Webs

To optimize the segment storage and hoisting plan of precast segmental composite box girders with corrugated steel web bridges, China’s first precast segmental composite girder bridge with corrugated steel webs is taken as the background. The difference between the precast segmental composite box girders with corrugated steel webs and the traditional concrete box girder is proven by numerical simulation. The stress and deformation characteristics of the segmental girder during storage and hoisting are analysed, and reasonable control measures are proposed. The data suggested that compared with ordinary concrete box girders, the smaller torsional stiffness and lateral stiffness of the precast segmental composite box girder with corrugated steel web segments lead to larger roof stress and deformation during the storage and hoisting periods. The number of storage layers of segmental girders should not exceed two, and the four hoisting point scheme should be adopted for hoisting. It is recommended to set one to two channel steel supports of no less than 20 grade steel between the top and bottom plates to avoid excessive deformation of the roof. With the increase in the segment length, the roof deformation and stress increased regardless of the storage period and the hoisting period. If the safety factor needs to be increased, when the segment length is short (1.6 m–3.2 m), increasing the support size is recommended. When the segment length is longer (4.0 m, 4.8 m), increasing the number of supports is recommended.

Study of Practical Analysis Method for Shear Warping Deformationof Composite Box Girder with Corrugated Steel Webs

Shear warping deformation is an important part of the flexural and constrained torsion analysis of composite box girder with corrugated steel webs (CBG-CSWs), which is also the main reason for the complex force analysis of box girders. A new practical theory for analyzing shear warping deformations of CBG-CSWs is presented. By introducing shear warping deflection and corresponding internal forces, the flexural deformation of CBG-CSWs is decoupled to the Euler-Bernoulli beam (EBB) flexural deformation and the shear warping deflection. On this basis, a simplified method for solving shear warping deformation using the EBB theory is proposed. According to the similarity of the governing differential equations of constrained torsion and shear warping deflection, a convenient analysis method for the constrained torsion of CBG-CSWs is derived. Based on the decoupled deformation states, a beam segment element analytical model applicable to EBB flexural deformation, shear warping deflection, and constrained torsion deformation is proposed. A variable section beam segment analysis program considering the variation of section parameters is developed for CBG-CSWs. Numerical examples of constant and variable section continuous CBG-CSWs show that the stress and deformation results obtained by the proposed method are in good agreement with the 3D finite element results, verifying the effectiveness by the proposed method. Additionally, the shear warping deformation has a great influence on the cross-sections near the concentrated load and middle supports. This impact along the beam axis decays exponentially, and the decay rate is related to the shear warping coefficient of the cross-section.

Distortion analysis of horizontally curved trapezoidal box girder bridges

Composite box girder bridges may be a competitive solution under certain constraints due to their efficiency and torsional capacity. However, the cross section deflects transversally, creating longitudinal stresses which reduce the capacity of the section. Those stresses may be controlled using cross-frames, but the detailing of those elements may become expensive. The procedure described herein provides a useful tool for an efficient design of cross frames based on the well-known BEF theory. It may be implemented using a commercial software and the formulation provided increases the accuracy of the existing one.

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.

The shear lag effect of composite box girder bridges with corrugated steel webs

The composite box girder bridge with corrugated steel webs has been constructed throughout the world since its debut in France in 1986 due to its various advantages. Since the shear lag effect is very essential to the safety of this kind of structure and it is seldom issued, in this paper a theoretical method is firstly developed based on the energy variational principle and then a finite difference solution procedure for the analysis of the shear lag effect of this kind of bridge. Afterwards, a new definition of effective flange width applicable to thickness-varying flanges is proposed. This new definition is then adopted to obtain the effective flange width coefficient that can indicate the characteristics of the shear lag effect. To validate the proposed semi-analytical method and to investigate the characteristics of shear lag effect, the semi-analytical method and finite element method are used to estimate the effective flange width coefficient of simply-supported and continuous bridges of this kind. The comparison of the two methods shows that the semi-analytical method can accurately predict the effective flange width coefficient. Under uniformly distributed loading, positive shear lag effect can be observed throughout the whole bridge when it is simply supported. For continuous bridges under uniformly distributed loading, the magnitude of shear lag effect in each span reduces with the increase of the effective span length. Finally, the applicability of technical provisions about effective flange width in design codes is studied, and some design suggestions are proposed for the effective flange width and the shear lag effect of this kind of bridge based on a comprehensive parametric study that is carried out using the semi-analytical method.

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.