Girder Web Research Articles

Stress increases in crane runway girders due to rail joints

AbstractVertically acting wheel loads from overhead bridge cranes and potential additional horizontal crane loads induce two types of stresses in crane runway girders: i) global stresses due to bi‐axial bending and torsion and ii) local stresses which mainly affect the girder's web. The latter typically represent one of the most decisive criteria for the fatigue design check of welded girders and are the focus of this paper. Crane rails with foot flange are typically connected to the top flange with rail clips. These clips maintain the position of the rail in vertical and horizontal transverse direction, but they generally allow for longitudinal movement of the rail. Rails with foot flange are used with and without elastomeric bearing pads between the rail and the top flange of the girder. The local stresses in the webs of crane runway girders are strongly affected by discontinuities of the crane rails. Such discontinuities can originate from unplanned rail cracks as well as planned rail expansion joints. The current mechanical models for concentric as well as eccentric wheel loading in relevant design standards assume continuous crane rails. However, rail joints are expected to significantly increase the local stresses in the region beneath rail joints. The present paper focuses on the impact of rail joints on the local stresses in crane runway girders. The research activities comprise experimental tests as well as finite element calculations. The aim of the investigations is to develop a better understanding of the mechanical behaviour in order to avoid future fatigue damage due to an unexpected increase of local stresses at a rail joint.

Stability behaviour of sinusoidal corrugated web girders under fire conditions

AbstractSinusoidal corrugated web girders, which are in the focus of the current paper, have been increasingly used in the past years in civil engineering applications due to economical design. Recently, a number of experiments dealing with the particular behaviour of this girder type have been carried out at room temperature, while the structural behaviour at elevated temperature has not been widely analysed and requires further investigation and clarification. The current paper deals with the improved geometrically and materially nonlinear analysis with imperfections (GMNIA) of sinusoidal corrugated web girders under fire conditions. The developed finite element model, which is validated based on previous measurements during fire tests found in the international literature, is capable of modelling the specialties, e.g., the so‐called ‘accordion effect’, of corrugated web girders. The applicability of design formulae is also illustrated in the paper while an extensive numerical parametric study is also carried out to demonstrate the impact of different parameters on the stability behaviour and failure mode of corrugated web girders at elevated temperature.

Bridge Construction Using Innovative Technology of Open Web Girder Launching

Bridge Construction Using Innovative Technology of Open Web Girder Launching

Experimental investigation on the performance of Cable-Girder anchorage structure of hybrid Cable-Stayed suspension bridges

As the key component of the stay cable connecting the girder and tower in the hybrid cable-stayed suspension system, the cable anchorage structure needs to bear the powerful cable force transmission function. Compared with normal anchorages, the structural features of a new type of anchor box structure cable-girder anchorage (CGA) that has strong bearing capacity and more uniform stress distribution for a long-span hybrid cable-stayed suspension bridge with steel box girder was investigated by a 1:2 scale specimen test and a series of finite-element analysis. Through finite element analysis (FEA) and test results, the stress distribution and cable load transfer pathway of anchor box structure are obtained. The test results show that the CGA design is reasonable and reliable. The four welds connected to the anchor box support plates and the steel box girder webs bear 87% of the cable force load transfer, and the remaining 13% of the cable load is delivered from the anchor box bearing plate to webs. A large stress concentration in the six welds, but the maximum von Mises stress (VMS) of welds is 130–151 MPa. According to the parametric studies,the installation angle of the anchor box considerably affects the stress characteristics. Also, the thickness and length of the anchor box plate are changed, the transmission and distribution proportion of the cable force between the main welds of the anchor box increase alternately.

Lateral torsional buckling analysis of corrugated steel web girders using homogenization approach

Corrugated web beams have become popular in recent years due to their high strength-to-weight ratio, ductility and high shear resistance without stiffeners. The developments in the automated production of corrugated steel plates have further amplified their use as structural elements in bridges and buildings. In this paper, we develop a strain energy-based homogenization scheme to convert corrugated sections into equivalent flat sheets with modified elastic properties. The thin-walled theory is implemented in a one-dimensional (1D) finite element (FE) framework along with a modified analytical expression to study the lateral torsional buckling of corrugated web girders. The homogenization-based FE modelling reduces the computational requirement of finer mesh sizes on the corrugation profile. The present thin-walled FE model is implemented to different corrugation profiles and lengths, and their responses are compared with methodologies available in the literature. The effects of the geometrical parameters and loading on the lateral torsional buckling behaviour are investigated and important observations are made for structural designs.

Shear behavior of stainless steel girders with corrugated webs

In this paper, the shear strength of corrugated web girders made of EN 1.4162/LDX 2101 stainless steel is investigated. Four full-scale trapezoidal corrugated web girders were tested under shear. Before conducting the tests, DIC was used to measure the real geometric imperfections in the web panels. Complementary finite element analysis studies were conducted to assess the sensitivity of the shear strength to initial imperfections. The experimental results indicated that all the tested girders with a local slenderness ratio of λ = 0.7 attained the shear yield strength, which was then followed by strain hardening in the material at a level that was 8–18% higher than the yield strength. This implies that the Eurocode's limit of λ = 0.25 to attain the plastic shear strength in corrugated webs can be quite conservative for stainless steel. According to the findings of the imperfection sensitivity studies, an initial geometric imperfection based on the first eigen buckling mode and with a maximum amplitude of amax/200, where amax is the maximum corrugation fold length, yielded ultimate strength within 3% of the test results. When the amplitude was increased to hw/200, where hw is the web height, the ultimate strength was estimated to be 25% lower on average than in the experiments. In three of the studied girders, initial imperfections with other forms than the first buckling mode were found to be more critical. Further, it was found that regardless of mode number, mode shapes that are more extended over the web panel result in a higher degradation of the ultimate shear strength.

Behavior study of the steel plate girder with a cellular honeycomb web

Based on the experimental test results of the authors, this investigation is concerned with the finite element analysis to examine and compare the load values and failure modes of the authors’ results. This research was conducted using the Abaqus software. The experimental work included the fabrication of twelve plate girders with honeycomb and flat web plate corrugation patterns, which were then tested under a single concentrated load at the midspan. According to the corrugation dimension or outer honeycomb web thickness, the honeycomb steel plate web girder is divided into three groups (60 mm, 80 mm and 100 mm). The specimens also involved plate girders with a flat web. The specimens were created with three lengths (600 mm, 1,200 mm and 1,800 mm). The Abaqus software was used in finite element models to simulate the concentrated load. The numerical results demonstrated that the 60 mm thick honeycomb web provides a greater load-bearing capacity and shear strength than other girders. The 20 mm honeycomb corrugation on the steel plate girder indicates the increased and improved shear resistance. The conclusion was that as the width of the corrugation increased, so did the steel web’s ultimate load and shear strength, resulting in a positive relationship between the critical shear buckling load of the web and the moment of inertia at the strong axis. When the dimension of the corrugation increases, the moment of inertia of the Y axis (Iy) decreases; thus, the plate girder will fail with a less critical buckling load (Pcr). Also, it can be concluded that as the steel plate thickness of the honeycomb web increases, the shear resistance increases as well. However, the spacing between the intermediate stiffener or the horizontal spacing of the web panel can enhance the shear resistance of honeycomb web girder if it was decreased due to increasing the action of tension field force that resists the diagonal tension developed at the web panel by the applied midspan concentrated force.

Impact of rail joints on the local stresses in crane runway girders

Vertically acting wheel loads from overhead bridge cranes and potential additional horizontal crane loads induce global stresses due to bi-axial bending and torsion and local stresses in crane runway girders which mainly affect the girder’s web. The latter typically represent one of the most decisive criteria for the fatigue design check of welded girders and are the focus of this paper. Crane rails with foot flange are typically used for moderate to high wheel loads. They are usually connected to the top flange with rail clips. Rails with foot flange are used with and without elastomeric bearing pads between the rail and the top flange of the girder. The local stresses in the webs of crane runway girders are strongly affected by discontinuities of the crane rails. Such discontinuities can originate from unplanned rail cracks as well as planned rail expansion joints. The current mechanical models for concentric as well as eccentric wheel loading in relevant design standards assume continuous crane rails. However, rail joints are expected to significantly increase the local stresses in the region beneath rail joints. The present paper focuses on the impact of rail joints on the local stresses in crane runway girders. The research activities comprise experimental tests as well as numerical parametric studies based on finite element calculations, both for rails with and without elastomeric bearing pads. The aim of the investigations is to develop a better understanding of the mechanical behaviour and to quantify the increase factor for maximum local stresses in order to avoid future fatigue damage due to an unexpected increase of local stresses at a rail joint.

Assessment of web shear stresses and shear capacity of FRP composite tub girders for highway bridges

Reinforced polymer composite tub (CT) girders are a novel solution as the main structural element of short to medium span highway bridges. These girders are lightweight and more durable than the steel and concrete bridges they are designed to replace. Although CT girders have been shown to behave well in flexure, significant questions remain as to the shear strength and buckling resistance provided by their foam-core sandwich webs, and regarding the distribution of shears under traffic live-load. Current practice is expected to provide conservative designs but could lead to inefficient material utilization, and few bridges have been placed in service to-date. In this study, CT girder sandwich web specimens were tested in near-pure shear in an attempt to assess their ultimate shear strength. The test results justify significant increases to the current web design strengths. A comprehensive suite of finite element analyses of typical girder webs was then analyzed to assess their shear buckling capacity. The analysis results were used to create design charts that provide critical web shear buckling loads for a range of web face sheet thicknesses, web foam core thicknesses, and web depths. Finally, a diagnostic field live load test of the first CT girder highway bridge placed in service is described, which focused on examining shear live load distribution. The results of this test indicate that the original design was reasonably conservative but demonstrate the need for live load distribution factors specifically tailored to the behavior of CT girders.

Dynamic response of a damaged bridge model traversed by a heavy point mass

The dynamic response of a single-span, damaged bridge model traversed by a point mass whose magnitude is comparable to that of the underlying girder is studied for the purpose of detecting structural damage. Damage is represented in the form of vertical cracks running across the girder's web, which modifies the eigenproperties of the original intact girder. The weight of the mass during its traverse time also modifies the eigenproperties of the girder and its motion produces an additional damping effect. Both features are modelled as Dirac delta distributions, one accounting for the spatial discontinuity in the slope of the deflection, and the other for the temporal discontinuity as the point mass moves forward with constant velocity. Although each type of discontinuity has been treated in the past, their combined effect has not been satisfactorily addressed. Next, a novel time-marching scheme is introduced for treating the temporal discontinuity, where the mass, stiffness and damping of the girder are all updated at the end of a given time interval. Then, the equations of motion are cast as a first-order, matrix differential equation. A parametric study has shown that two eigenvalue-eigenfunction pairs are sufficient for convergence purposes. Following modal synthesis, the transient velocities at any point on the girder during both forced and free vibration regimes are processed by the short-time Fourier transform as a means for detecting changes in the resulting spectograms that are attributable to damage. Finally, support failure is also examined by the introduction of flexible translational springs at the ends. The methodology developed here can be used to identify damage from the recorded kinematic spectrograms at any station on the span of the girder due to a travelling mass. In closing, this work finds applications in structural health monitoring of structures, which is a contemporary and challenging problem facing the engineering profession.

Experimental and numerical investigation on patch loading capacity of longitudinally stiffened hybrid titanium-clad bimetallic steel plate girder

Plate girders are important load-bearing components of bridge and industrial structures. Corrosion significantly affects durability and service life of plate girders. Bimetallic steel consisting of corrosion-resistance metal and metal with superior mechanical properties provides an engineering solution for the mitigation of corrosion. The titanium-clad bimetallic steel (TCBS) was innovatively introduced into the plate girder as the web to solve the corrosion issue, where the nonlinear resistance performance and failure mode of a longitudinally stiffened hybrid TCBS plate girder under patch loading were investigated experimentally. The test results prove that the longitudinally stiffened hybrid TCBS plate girder has stable load-bearing performance, which is similar to that of the conventional mild steel plate girder. Effects of the shape and magnitude of the initial geometric imperfection on the resistance behavior of the longitudinally stiffened hybrid TCBS plate girder were investigate numerically. A parametric study on the effects of the material properties, longitudinal stiffener location, relative flexural rigidity of the longitudinal stiffener, web panel aspect ratio, and web height-to-thickness ratio on the resistance and critical buckling behaviors of a longitudinally stiffened hybrid TCBS plate girder was performed. Considering the strain strengthening properties of TCBS, the ultimate resistance and ductility of longitudinally stiffened hybrid TCBS plate girders can be significantly improved without affecting the buckling performance. The effect of key parameters on the longitudinally stiffened hybrid TCBS plate girder is consistent with that of the conventionally stiffened mild steel plate girder. Therefore, it is a feasible solution to apply TCBS to the plate girder web, which performs a beneficial effect on the durability of the plate girder.

Estimation of patch-loading resistance of steel girders with unequal trapezoidal web-corrugation folds using nonlinear FE models and artificial neural networks

Corrugated-web steel I-girders (CWGs) have better shear and torsional strengths, offering additional stability against out-of-plane web buckling and local crippling under patch loads than flat web girders. CWGs are lightweight and more cost-effective than flat web beams for applications in buildings and bridges. The existing design models for estimating patch-loading resistance in CWGs assume equal widths in web corrugation folds for a simply supported span. This study examined the parametric influence of unequal trapezoidal-web folds on the nonlinear behavior of CWGs under compressive patch loading. A total of 533 steel I-girders with simply supported (SS) and 478 cantilever spans (CS) were analyzed using a calibrated nonlinear finite element (FE) methodology. The generated datasets of CWGs consisting of governing parameters (i.e., girder geometry and material properties) were mapped to refined patch-loading resistance using artificial neural networks (ANNs) for both CS and SS-type spans. The proposed ANN formulation showed better prediction accuracy (mean absolute error of about 2–4% in this study) than the existing design models for estimating the patch-loading resistance of CWGs. For practical applications and conservative patch-loading resistance, prediction modification factors were also proposed for ANN formulation and existing design models within a targeted error margin.

Local bearing capacity of steel beam webs with random pit corrosion

H-shaped steel beams are widely used in architectural and industrial structures, such as bridges, offshore platforms, and industrial equipment. However, corrosion seems to be inevitable during the service of steel beams, with pitting being one of the most common corrosion types. The local bearing capacity of the steel girder web is one of the most important factors affecting the stability of steel structures. In this work, the stochastic finite element method is used to reveal the effect of pit corrosion on the local bearing capacity of the corroded H steel girder web, and the relationship between the local bearing capacity of the web and the mass loss rate is also discussed. The effects of specific and random corrosion positions on the local bearing capacity of webs, as well as random corrosion thickness and constant corrosion thickness on the web thickness, are analyzed. Moreover, the effect of the reduction coefficient on the probability distribution model is studied, and the variation of the reduction coefficient with the probability distribution model of corrosion thickness is revealed. The conclusions in this work can provide a theoretical analytical basis for the evaluation of the local bearing capacity of H-shaped steel beams with randomly corroded webs.

Flexural behavior of printed concrete wide beams with dispersed fibers reinforced

Thanks to the highlighted advantages of the construction method, including digitalization and automation, sustainable materials, and environmental protection, 3D concrete printing technology has been a hot topic for a few decades. This construction method was initially used in small and non-structural applications and is now being adopted for large-scale structures. This transition requires a lot of research on the structural behavior of structures. Therefore, the study focuses on the behavior of wide beams, which is the primary element in the structure system. Nine wide beams with different glass/steel fiber amounts were printed, and 3-point loading tests were conducted. The failure mode, flexural strength, deflection, and ductility were reported in this study. In this study, the girder web was designed in the style of truss beams, and glass/steel fibers were used. The fibers, including glass and steel fiber, will enhance the beams' flexural strength and ductility. The results showed that (1) The adhesion force between the printed layers ensures the overall working of the wide beams; (2) The failure patterns of glass fiber beams were brittle; glass fibers show insignificant improvement in compressive strength; the flexural capacity was significantly enhanced, and the optimal steel fiber amount is 1.0%. (3) The failure patterns of steel fiber beams were ductile; steel fibers showed light improvement in compressive strength. The steel fiber significantly impacted the flexural strength. The optimum amount of steel fibers was determined to be ranged from 1.0% to 1.5%.

Flexural performance of prefabricated composite beams with grouped bolt shear connectors under positive bending moments

Four prefabricated steel–concrete composite beams (PSCCBs) with grouped bolt shear connectors were designed and tested to investigate their flexural performance under positive bending moments. The effect of shear connection degrees and segmented precast concrete (PC) slabs on the flexural performance of PSCCBs was investigated. Experimental results show that all the specimens failed due to the yielding of steel girders and concrete crushing in the mid-span regions, presenting typical characteristics of flexural failure. Compared to the PSCCB with a monolithic PC slab, the PSCCBs with segmented PC slabs experienced a short fast increasing stage of mid-span deflection after the steel girders yielded, of which the initial flexural stiffness and ductility coefficient decreased by 47.8% and 44.1% at most, respectively. Then, finite element (FE) models of PSCCBs with different design parameters were developed to assess their flexural behaviors under positive bending moments. Numerical results demonstrate that the initial flexural stiffness was significantly affected by the girder web height and the length of the middle PC slab. Enlarging the gap width, the length of the middle PC slab, and the girder web height are beneficial for the ductility of PSCCBs. The research findings might provide references for the design of PSCCBs with segmented PC slabs and grouped bolt shear connectors.

Comparison of the Efficiencies of Web Cutouts for Steel Plate Girders with Corrugated Webs Versus Flat Webs Under Pure Shear

Abstract Corrugated steel-plate girders are used as structural elements in many applications because of their properties, cutouts are always provided in these plate elements to enable inspection and servicing. This study presents an experimental and analytical study to investigate the efficiency of a steel-plate girder with corrugated webs (GCWs) and flat webs (GFWs) having cutouts under shear loading. In this study, we investigated the influence of some important parameters on the girders’ load-bearing capacity. The experimental program was conducted on six full-scale plate girders, which have been tested under central load at mid-span. The analysis was conducted using ANSYS V20 to perform a nonlinear technique for the determination of the ultimate load of the tested girders. Finally, experimental and finite element model were used to define the ratio of increasing carrying capacity in plate girder with flat and corrugated web, having cutout under shear loading. The ultimate strength, failure mechanism, and load-deflection curves from the experimental and analytical study show that the shear capacity of the girder with corrugated web girders extends loads by 22 % compared with the flat web.

Analysis on the shear failure of HSS S690-CWGs via mathematical modelling

This paper aims to present a new and accurate design equation by employing the applications of deep learning and mathematical modeling techniques in calculating the shear strength and the failure mode of corrugated web girders (CWG) formed by S690 high-strength steel (HSS). HSS provides slenderer and weight-efficient structures than those would be possible if ordinary-strength steels were used, while the corrugated web (CW) increases the shear stability of steel girders and eliminates the need of transverse stiffeners. Therefore, the CWGs and HSS can be combined into one structure for gaining more structural benefits for civil engineering applications. A finite element (FE) model is firstly established and verified by the available experimental data in the literature. Thereafter, 106 FE models of CWGs are generated and analyzed, then employed in deep learning and mathematical modeling techniques such as the neural network (NN) and Kriging model, respectively. This investigation helps to present a new mathematical model able to predict the shear strength of S690-CWG with almost zero mean square error. The predicted results via the new equation agree well with those via the experimental tests, FE analysis and NN predicted data. Moreover, the comparative results show that the currently proposed equation gives an accurate or even exact shear strength of S690-CWGs than thus via the existing equations in the literature. Finally, an extensive parametric study has been established to investigate the influence of the CWGs’ geometrical perimeters on the shear strength of S690-CWGs.

A novel composite thermal insulation system for concrete bridge box girder and its influence

The temperatures of a concrete box girder were observed through a field test, and the finite element method (FEM) model of the concrete box girder was established. The unknown parameters were inversed by using the constriction coefficient particle swarm optimization (CCPSO) algorithm, and hence the optimized numerical model of the temperature field close to the real-world temperature field was obtained. A novel set of composite thermal insulating system for a bridge is developed for the first time, in which the insulation coating on the outside surface of the box girder web and bottom plate is combined with the thermal insulation deck pavement layer of the bridge. The coating is insulating mortar consisting of gelatinous power and expanded polystyrene (EPS) pellets, and the insulation deck pavement layer is made of ceramsite asphalt mixture. The research results show that the proposed thermal insulation system can effectively reduce the average temperature and temperature gradient of the concrete box girder. In addition, the influence of the materials and thickness of deck pavement and coating on box girder temperature is analyzed. It provides theoretical guidance for reducing bridge temperature.

The Amelia Earhart network tied arch bridge replacement project, MO, USA

A replacement for Amelia Earhart Bridge, carrying Highway 59 across the Missouri River (MO, USA), has been constructed. Interactions between the flow around this bridge and two existing bridges adjacent to the new bridge had the potential to create large scour holes. As the original bridge needed to remain open during the construction of its replacement, a scour study was performed to determine the placement of the piers. The new bridge uses prestressed concrete bulb T-girder spans for the approaches and one 160.6 m (527 ft) steel network tied arch for the main navigation span. The bridge was designed in 2008 and was one of the first modern tied arch bridges in the USA to use internal redundancy for fracture-critical members using bolted angles at the intersection of the tie girder webs and flanges. Due to vertical clearance constraints, the tied arch contains a framed-in-floor system to minimise the depth of the structure. This also required a specific slab pouring sequence to relieve the elongation effects of the tie girder during construction. This signature structure opened to traffic in 2012 and project completion occurred in summer of 2013. This paper focuses on the pier placement relating to scour concerns and the design of the tied arch span.

Investigation the Ductility of Corrugated Embedded Shear Connectors Through Push‐out Tests

AbstractThe most widely used shear connector of steel‐concrete composite beams is the well‐known headed stud and it can be used for innovative bridge girders with trapezoidal webs embedded in concrete slab as well by horizontally placing the studs on the embedded steel part. Another option for trapezoidal web girders is the closed or open cuts on the corrugated web profile with rebars. In literature, experimental tests and investigation of these kind of shear connectors of embedded steel webs can be found. The focus of the research presented in the paper is on the ductility of embedded trapezoidal corrugated webs with additional mechanical shear connectors. Previous researches have already found that these kind of innovative shear connections have a really advantageous ductile behavior, however further analysis is useful to confirm and investigate their behavior in more details. Force‐displacement diagrams of push‐out experiments of corrugated steel profiles embedded into concrete slab are published in literature and those diagrams serve as a basis of this study. Both elastic and plastic phases of the curves are evaluated, also ductility is analyzed according to the principles of Eurocode.