Composite Plate Girders Research Articles

Negative bending capacity prediction of composite girders based on continuous strength method

This paper investigates the ultimate negative bending capacity of composite plate girders, whose ultimate hogging flexural state is governed by the local buckling of the bottom flange of steel girders. The Continuous Strength Method, a deformation-based design approach, which employs a continuous relationship between cross-sectional slenderness and inelastic local buckling deformation capacity, is adopted to accurately predict the ultimate negative bending capacity of composite plate girders. A large number of composite cross-sections, which could represent the conventional cross-section of composite plate girder bridges with medium spans, are designed along with various combinations of steel girder strengths and rebar strengths. For each composite cross-section, its ultimate negative bending capacity based on CSM, ultimate elastic bending capacity, and rigid plastic bending capacity are calculated and compared mutually. Both linear and quadratic interpolation equations are proposed for simplifying the negative bending capacity prediction of the composite section. The analysis results indicate that the linear interpolation bending capacity predicting equation can produce relatively conservative results for most Class 2 and Class 3 cross-sections but the equation is quite concise for application. The quadratic interpolation bending capacity predicting equation can offer more accurate results, especially for cross-sections of which the bottom flange governs the ultimate elastic flexural state rather than the rebar in concrete slabs. The rebar in concrete slabs, the top flange and bottom flange of steel girders are supposed to enter into yield state simultaneously for improving the elastic negative bending efficiency of the composite section. Meanwhile, the proposed quadratic interpolation equation could also provide an accurate negative bending capacity prediction.

Experimental and analytical studies on bearing capacity of bolt connected composite plate girders

Composite plate girders bearing the enormous concentrated loads from boilers are common members in thermal power plants. Because of their large scale and sustaining distinct loads, the section of these girders is made of two parts combined with high strength bolts. Experimental investigations on two I-section plate girders, two homogeneous composite girders, and two hybrid composite girders, are implemented. Bearing capacity and member ductility are compared among the three kinds of specimens. To reveal the mechanism of composite plate girders, force method built upon the linear elastic theory is employed, according to deformation coordination among the components. The elastic stress distribution predicted by the analytical method is validated against test data. Based on the internal force distribution derived, the elastic effective width method in current specifications and the plastic effective width method proposed in other published literature are employed herein to predict the critical load. Conclusions can be made that bearing capacity of composite girders is superior to the I-section ones, and hybrid composite plate girders can further balance the economic and mechanical efficiency of constructions. Additionally, several proposals for application are offered.

Effect of Strain Hardening on the Flexural Resistance of Composite Plate Girders Using HSB600 High-Performance Steel in Positive Bending

Effect of Strain Hardening on the Flexural Resistance of Composite Plate Girders Using HSB600 High-Performance Steel in Positive Bending

Strain Behaviour in Composite Plate Girders with Imperfect Shear Connection

This paper is concerned with the experimental study on the behaviour of strain in steel-concrete composite plate girders having imperfect shear connection. A number of slender girders of practical size were loaded to failure under shear applied at the mid-span. The main variables considered in this study are the longitudinal spacing of stud connector, diameter of stud shank, number of studs along the upper flange and concrete strength. Strains were measured extensively at specified load levels and locations across the concrete slab width and across the whole depth of the girder. The test results have shown variations of strain from girder to girder due to effects of reaction at supports, compression and tension parts of the girders as well as imperfection in the shear connection. Strains across the slab width show arbitrary respond with maximum tension and compression values of 4284μɛ and 4622μɛ, respectively. Across the girder depth, girders with low degree of shear connection display high step change to the extent of 736μɛ due to incompatibility between two strains at the interface. Slip strain is found maximum near the mid-span of the girders in all cases.

Structural Characteristics of Steel-Concrete Composite Plate Girder with Arch-Type Web Stiffener

In this paper, we present the result of analytical investigation pertaining to the structural behavior of steel-concrete composite plate girder with arch-type web stiffener. In the arch-type web stiffener located in the compression side of web, infill concrete is cast to strengthen the arch-type stiffener and also to exert resisting force against compression force. This type of composite steel-concrete plate girder bridge is built and is in service. To understand the behavior thoroughly, analytical parametric study was conducted by using the finite element method. As a result it was found that the effect of arch-type stiffener with infill concrete is considerable for the design of such type composite girder bridge.

Structural analysis of a composite continuous girder with a single rectangular web opening

In the design of most bridge girders with composite girders composed of steel–concrete composite plate girders, an opening in the steel girder is often used to provide passage for utility ducts and pipes. This results in significant savings in material and construction costs. So it is necessary to study the effect of an opening in the web steel on the behavior of the composite girders if the designer wishes to provide adequate opening in the structural elements without reducing its load carrying capacity.In this paper, a non-linear finite element analysis has been done to analyze the deflection in the steel section and internal stresses in the concrete slab for continuous composite girders with a single rectangular opening in the steel web. ANSYS computer program (version 15) has been used to analyze the three-dimensional model. The reliability of the model was demonstrated by comparison with experimental results of continuous composite beams without an opening in the steel web carried out by another author. The parametric analysis was executed to investigate the width, height, and position of the opening in one span on the behavior of a composite girder under vertical load. The results indicated that when the width of opening is less than 0.05 of length of a single span and the height is less than 0.15 of the steel web, the deflection and internal stresses increased less than 10% comparing to continuous composite girders without an opening.

Behavior and Response of Headed Stud Connectors in Composite Steel Plate Girder Bridges under Cyclic Lateral Deformations

Most of the mass of steel plate girder bridge superstructures is concentrated in the reinforced concrete deck. During a seismic event, the inertia force that is generated in the reinforced concrete deck is transferred to the support cross frames through the headed stud connectors. Seismic analyses showed that these connectors are subjected to combined axial tension and shear forces. If not designed properly, these connectors may fail prematurely during an earthquake, altering the load path and subjecting other bridge components to forces they are not designed for. To verify these observations, two half-scale models of plate girder bridge subassembly were constructed and subjected to cyclic testing. The two specimens represented two different configurations of headed stud connectors in transferring the deck seismic forces. The connectors in the first specimen connected the girder top flange to the reinforced concrete deck, while the connectors in the second specimen connected the cross-frame top chord to the deck. These experiments showed that the connectors were indeed vulnerable under transverse lateral loading. The failure mode of these connectors is a combination between shear and tensile forces or concrete breakout. Based on this investigation, design equations were proposed and adopted in the AASHTO LRFD Bridge Design Specifications to evaluate the resistance of such connectors under shear and tensile forces.

Tests of partially connected composite plate girders

This paper is concerned with the strength and behaviour of partially connected composite plate girders. Eight simply supported composite plate girders were tested to failure under a concentrated load applied at the mid-span. The main variables considered in this study are the longitudinal spacing of stud connector, diameter of stud shank, number of studs along the upper flange and concrete strength. Test results have shown considerable variations in ultimate strength, behaviour and failure characteristic in all specimens due to effects of partial interaction. An analytical method to determine the ultimate strength of partially connected composite plate girders is outlined. Three-dimensional non-linear finite element analyses are also carried out on the girders using the general purpose computer code, LUSAS. Results obtained through the analytical method are compared with the corresponding finite element and experimental ones in respect of ultimate load, load–deflection response and deformation behaviour. Reasonably close agreement between the results establishes the accuracy of the analytical method and finite element simulation.

Web Buckling and Ultimate Strength of Composite Plate Girders Subjected to Shear and Bending

The paper is concerned with ultimate load behavior of steel–concrete composite plate girders subjected to combined action of shear and bending. An analytical method is presented to predict the interactive response of the girder. The method considers the tension field action in the plate girder web panel and shear failure of concrete slab. The method is approximate and can be applied to composite plate girders at the preliminary stages of design. Strength of composite plate girders is investigated by varying the moment/shear ratio. It is shown that ultimate load capacity of composite plate girder is influenced by moment/shear ratio. The predicted results are compared with the corresponding finite-element values.

Effects of partial interaction on the behaviour of composite plate girders

This paper is concerned with a series of tests on steel-concrete composite plate girders with partial shear connection. Eight simply supported girders of practical size were tested to failure in order to examine the responses under shear load applied at the mid-span. Effects of different shear connection properties and concrete grades on the ultimate strength and behaviour of the girders are the main focus of the study. Variations of strength, mode of failure and load-deflection behaviour have been observed. The ultimate load capacity was found to drop significantly and the behaviour has changing from brittle-like to ductile mode as the degree of interaction reduced.

Experimental study on composite plate girders with web opening

The paper is concerned with an experimental investigation on simply supported steel–concrete composite plate girders containing web openings. Ten composite plate girders were tested to failure in order to study their ultimate strength behaviour. Effect of web openings on the ultimate load behaviour of composite plate girders is of primary concern in this study. Test results show that the ultimate shear strength drops marginally in girders with smaller openings but the drop is significant in girders with larger openings, larger than 0·3d, with d being the web depth. The test specimens were also analysed using an analytical method and a finite-element modelling and the predicted results compared with the corresponding experimental values. The comparison shows good agreement, thus confirming the accuracy of the analytical method and finite-element modelling.

Assessment of vehicular live load and load factors for design of short-span bridges according to the new Egyptian Code

The new Egyptian Code (ECP-201:2012) introduces new vehicular live loads (VLL) and new load combinations for the design of roadway bridges. The new VLL and load combinations introduced in ECP-201:2012 are fundamentally different than those presented in previous versions of the code. The impact of these new loads and load combinations on the design of new bridges or the structural safety of the existing bridges that have been designed according to ECP-201:2003 or ECP-201:1993 has not been fully addressed for the different bridge deck systems. Three different bridge deck systems, i.e. concrete I-shaped girders, composite steel plate girders, and concrete box-girders with different spans were numerically modeled using two-dimensional grillage analogy. The bridge decks were analyzed under main gravity loads using VLL according to ECP-201:2012 and ECP-201:2003. The internal forces of individual load cases, total un-factored load combination, and total factored load combination of ECP-201:2012 and ECP-201:2003 were compared.The study shows that concrete box-girders designed according to ECP-201:2012 and ECP-201:2003 using the ultimate limit state method yield almost the same demand. Despite the increase in the VLL of ECP-201:2012, and consequently the live load forces, concrete I-shaped girder bridges will be subjected to less total factored internal forces in comparison to ECP-201:2003 This is attributed to the interaction between the live to dead loads ratio and the load combinations. Design of composite steel plate girder bridges according to ECP-201:2012 using the allowable stress design method yields over designed sections.

AN APPROXIMATE METHOD FOR THE ULTIMATE SHEAR STRENGTH OF HORIZONTALLY CURVED COMPOSITE PLATE GIRDERS

The paper is concerned with the ultimate load capacity of horizontally curved composite plate girders. An approximate method to predict the ultimate shear strength of the girders is presented. The proposed method accounts for the tension field action in web panels, composite action between steel plate girder and reinforced concrete slab with full interaction and presence of web openings. The accuracy of the method is assessed by comparing the predicted values of ultimate shear strength with the corresponding results obtained by using the nonlinear finite element analyses through a computer package LUSAS. The comparisons show that the proposed method is capable of predicting the ultimate shear strength with an acceptable accuracy. Presence of web openings of different proportions and their effects on ultimate strength of the girders are examined. Girders with trapezoidally corrugated webs are also considered in the study.

BEHAVIOUR OF COMPOSITE PLATE GIRDERS WITH PARTIAL INTERACTION

This paper is concerned with the behaviour and strength of composite plate girders in which, the interaction between the steel plate girder and concrete slab is partial. Based on curvature compatibility principle, an approximate method is proposed from which, the shear capacity and deflection at any given load may be determined. The tension field action developed in web panels at the post-buckling stage is incorporated in the solutions. From the results obtained by using the proposed method, it is found that the flexural stiffness and failure load drop with decrease in degree of interaction. Comparisons are made between the results obtained through the proposed method and the corresponding ones from finite element analysis. A satisfactory correlation between the results in terms of behaviour and strength establishes the accuracy of the proposed method.

강합성 박스거더 복부판의 탄성전단강도 연구

It is same such as the provision of shear buckling strength of steel composite box girder web panel and plate girder web panel in Korea Highway Bridge Design Standards(2012). But the web panel of steel composite box girder is different from the web of plate girder in that the upper slab and lower flange are connected to the web. So a different shear behavior of the girders is expected. In this study, To calculate a reasonable elastic shear buckling strength of steel composite box girder web panel, ABAQUS program was used. The results from F.E.A and previous studies are compared. It is shown that the web shear buckling strength of steel composite box girder of Korea Highway Bridge Design Standards(2012) is the most conservative.

Behaviour of partially connected composite plate girders containing web openings

This paper is concerned with an approximate method to predict the bending behaviour and ultimate strength of partially connected composite plate girders. Based on curvature compatibility, analytical solution incorporating post-buckling effect in the webs and different degree of shear connection is presented herein. Slender girders with centrally placed square or circular web openings of various proportions are considered in the analysis. The obtained results are verified against the corresponding ones using the established finite element method. A satisfactory correlation between the findings establishes the accuracy of the proposed method to a certain extent. Results are presented in the form of ultimate strength and load-deflection response for girders with variations in shear connection stiffness.

An analytical method for ultimate shear strength of composite plate girders with web openings

The paper presents an analytical method to determine the ultimate shear capacity of composite plate girders containing web openings. Since one of the flanges of the steel girder is connected to reinforced concrete slab through shear connectors the behavior differs from that of a bare steel plate girder. The analysis of such behavior is complex and hence it is necessary to have a simple method for design office use. A simple analytical method to determine the shear strength of the girder is presented herein. The method considers the effects of composite action between the concrete deck and steel part of the girder and the presence of openings in the webs. Contributions to the shear strength of the girder by tension field action in the plate girder web panel and shear failure of concrete slab are accounted for in the proposed method. The accuracy of the method is assessed by comparing the predicted values with the corresponding experimental results. Effects of web openings on ultimate shear capacity of composite girders are investigated.

Long term behavior of precast concrete slabs of a continuous composite plate girder prestressed longitudinally by sequential jacking-up and down method

Long term behavior of precast concrete slabs of a continuous composite plate girder prestressed longitudinally by sequential jacking-up and down method

Effect of Concrete Slab on Shear Capacity of Composite Plate Girders under Positive Moment

To evaluate the contribution of the concrete slab to the shear resistance of composite concrete-steel plate girders, two tests were carried out on one full-scale composite plate girder. The tested specimen was loaded to failure under shear load and positive moment. Vertical deflection of the girder and out-of-plane deflection of the web panels were monitored during each test. Principal strains and their inclination were obtained by instrumentation on the web, flanges, stiffeners, and concrete slab. The observed failure mechanism of the tested specimen is presented using the test results. Nonlinear finite-element analysis of the tested specimen was carried out and calibrated using the tests results. To study a wider range of composite girders, further finite-element models were built with different concrete slab and steel web thicknesses. The experimental and analytical results indicate that the ultimate capacity of the tested composite specimen is higher than what is predicted by the current AASHTO design specifications for a bare steel plate girder.

Collapse Behavior of Composite Plate Girders Loaded in Shear

This paper is concerned with the ultimate shear capacity of steel-concrete composite plate girders in which one of the flanges of the steel girder is connected to reinforced concrete slab through shear connectors so that the steel girder and the slab act compositely as a single unit. The analysis of such girders becomes complex and it is necessary to have a simple method for design office use. Therefore, an attempt is made in this paper to propose an analytical method to determine the shear strength of a web panel in the girder. The method considers the tension field action in the plate girder web panel and shear failure of concrete slab. The method is approximate and can be applied to composite plate girders at the preliminary stages of design. The predicted results are compared with the corresponding experimental values for girders tested by other researchers and also with finite-element predictions. The predictions are found to be accurate enough for any design office use.