Transverse stiffeners for plate girder webs—an experimental study

The paper describes nine tests on two large-scale, transversely stiffened plate girders. The objectives of the tests were to determine the ultimate load capacities, to study the modes of failure and, in particular, to investigate the behaviour of the transverse web stiffeners.The results obtained show that the tension field mechanism approach is capable of predicting the ultimate load capacities of girders with widely differing values of web panel aspect ratio, including girders with closely spaced stiffeners. The new design code for steel bridges, BS 5400, is shown to give slightly, but not unreasonably, conservative values of girder capacity.The tests have also shown that the methods currently proposed for the design of transverse web stiffeners are safe but conservative. The detailed observations of stiffener behaviour reported in the paper should facilitate future development of improved methods of stiffener design.     

Shear resistance in stainless steel plate girders with transverse and longitudinal stiffening

This paper summarizes and presents main results of the investigation conducted in the Department of Construction Engineering of the UPC dealing with shear behaviour of stainless steel plate girders. Initial shear buckling stress together with ultimate shear capacity of these structural elements have been evaluated with special attention paid to the effect of including stiffeners, both transverse and longitudinal. The studies conducted, both numerical and experimental tests, have permitted the development of new and simple design expressions to determine more accurately the initial shear buckling stress in stainless steel web panels and the ultimate capacity of plate girders considering the presence of a rigid or non-rigid end post.     

Investigation on the Collapse Behavior of Diagonal Stiffened Composite Plate Girders Subjected to Shear Loading

In this study, a new analytical method is presented to estimate the shear capacity of diagonally stiffened steel–concrete composite plate girders. This method is formulated based on tension field action in steel girder web and failure mechanism of concrete slab deck. To validate the accuracy of the proposed method, the obtained results are compared with three-dimensional finite element analysis of composite plate girders with different configuration of stiffeners. The results of analytical and numerical investigations indicate that the proposed method can accurately estimate the ultimate shear capacity of composite plate girders. In addition, it is shown that the diagonal stiffeners on one hand can reduce the buckling effects of shear panel of girders and on the other hand can increase the strength of elastic shear buckling and ultimate shear capacity of girders well in comparison with the unstiffened thin steel plate girders.     

The influence of longitudinal web stiffeners upon the collapse behaviour of plate girders

This paper describes eighteen tests carried out to study the influence of longitudinal web stiffeners upon the collapse behaviour of plate girders. The results of tests in which the stiffeners proved adequate are compared with those involving inadequate stiffeners and with tests on unstiffened girders. It is observed that, whereas girders with adequate stiffeners, in common with unstiffened girders, develop a stable failure mechanism, girders with inadequate stiffeners show a sharp drop from the maximum load, followed by the formation of a failure plateau at a reduced load level. Ultimate load capacities predicted by a tension field mechanism approach show satisfactory agreement with experimental values and current British and American design proposals are observed to provide conservative estimates of capacity.     

Web openings in horizontally curved composite plate girders

The paper is concerned with the effects of circular or square web openings on the ultimate strength of horizontally curved composite plate girders. Finite element analysis using the computer package LUSAS has been employed to investigate the behavior and ultimate strength capacity of the girders with web openings of different proportions. The opening sizes and their locations within the web panels have been studied in detail, and the results are presented in the form of load–deflection and load–opening size plots. An approximate method to determine the ultimate strength capacity of horizontally curved composite plate girders accounting for the presence of web openings and composite action between the steel girder and concrete slab is presented. The accuracy of the method is established by comparing the predicted strength with the corresponding values predicted by the finite element method.     

On the design of stiffeners in steel plate shear walls

This paper describes a numerical investigation to provide a practical design method for stiffening thin steel plate shear walls. The procedure considers one-sided transverse and longitudinal flat stiffeners located in various arrangements on shear plates which effectively divides the plate into subpanels and expands tension fields across the infill walls. The results obtained from several nonlinear static analyses are employed to draw applicable empirical relationships for evaluating optimal dimensions of stiffeners. The procedure also ascertains the effects of optimised stiffeners on the postbuckling behaviour and ultimate load bearing capacity of stiffened shear walls.     

Openings in horizontally curved plate girder webs

Ultimate strength tests on plate girders curved in plan containing centrally placed circular web openings are reported. Girders, built up of Grade 43A rolled steel plates, were tested to failure and parameters studied include opening size and degree of curvature. Test results show that the ultimate load capacity of the girders dropped linearly with the increasing opening size. Decrease in ultimate load carrying capacity with increasing degree of curvature is also observed for curved girders having smaller web openings. The failure mechanism observed in the tests was similar to that observed in plate girders without web openings, the only difference being the position of plastic hinges on the flange plates. The girders were analysed using the elasto-plastic finite element package, ABAQUS. Comparison of analytical predictions with the experimental results for deflected profiles, ultimate load values and load-deflection relationships show good agreement.     

Performance of composite girders strengthened using carbon fibre reinforced polymer laminates

This paper highlights the structural performance of steel–concrete composite girders strengthened using advanced composite laminates. Nonlinear 3-D finite element models have been developed to investigate the flexural behaviour and load carrying capacity of the girders. The composite laminates comprised carbon fibre reinforced polymer (CFRP) plates and sheets as well as steel reinforced polymer (SRP) sheets. The elastic modulus and ultimate tensile strength of the laminates varied from low to high 60–300 GPa and 700–3100 MPa, respectively. The nonlinear material properties of the strengthened composite girder components comprising concrete, structural steel beam, reinforcement bars, adhesive and composite laminates were incorporated in the finite element model. The interfaces between the composite girder components were also considered allowing the contact and bond behaviour to be modelled and the different components to retain its profile during the deformation of the strengthened composite girder. Furthermore, the load-slip characteristic of headed stud shear connectors was incorporated in the finite element models based on previous experimental and numerical investigations conducted by the author. The finite element models have been validated against published tests on composite girders strengthened using different advanced composite laminates and having different cross-section geometries, lengths, layers of laminates with different elastic moduli and ultimate tensile strengths, concrete strengths and structural steel strengths. The load carrying capacity of strengthened composite girders, load–vertical displacement behaviour and failure modes were predicted from the finite element analyses and compared against test results. Parametric studies were conducted to study the effects on the load carrying capacity and structural behaviour of strengthened composite girders owing to the change in the composite laminate elastic modulus, number of laminate layers, concrete strengths and structural steel strengths. The study has shown that the increase in the load carrying capacity and ductility of strengthened composite girders due to the increase in steel beam strength is significant with high strength concrete slab. Also, it has been shown that the increase in concrete strength offers a considerable increase in the initial stiffness of strengthened composite girders, while the increase in structural steel strength offers a considerable increase in the stiffness of strengthened composite girder in the post-yielding stage.     

Design of horizontally curved plate girder webs containing circular openings

A simple design method to predict the ultimate shear capacity of horizontally curved plate girder webs containing centrally placed circular openings, and subjected to shear is presented in this paper. The solution is obtained by incorporating the effects of curvature and opening size to an equilibrium equation for straight girders containing web openings. It is observed from a parametric study that ultimate load carrying capacity drops linearly with increasing degree of curvature for curved girders having smaller web openings. No significant drop in ultimate capacity is, however, observed when the web opening size exceeds half of the web depth. Accuracy of the proposed equation is assessed by comparing the results with the corresponding finite element values as well as with available experimental results. A satisfactorily correlation has been observed.     

A theoretical investigation of the collapse of multi-cellular structures under lateral loading

This paper describes the development of the grillage method to take into account the effects of shear, as well as bending, upon the non-linear and collapse behaviour of multi-cellular structures under lateral loading. The modified theory is outlined and the results obtained from the analysis of eleven girders are presented. In each case, the mode of failure is discussed together with the predicted ultimate load capacity. The results show the influence of varying structural proportions, including the addition of flange stiffeners, and of different support and loading conditions upon the girder behaviour.     

方钢管混凝土框架-十字加劲薄钢板剪力墙结构水平承载力研究

为研究方钢管混凝土框架-十字加劲薄钢板剪力墙结构的抗震性能和水平承载力,进行了一榀缩尺比为1∶3的2层单跨方钢管混凝土框架-十字加劲薄钢板剪力墙结构的拟静力试验,得到了其破坏形态、荷载-位移滞回曲线、骨架曲线、特征荷载和位移等。利用有限元软件ABAQUS对其进行了非线性数值模拟,分析了方钢管混凝土框架-十字加劲薄钢板剪力墙的抗震性能、受力机理和破坏机制。基于试验和数值模拟结果,结合理论研究,提出了方钢管混凝土框架-十字加劲薄钢板剪力墙的水平承载力的计算式,并将其计算结果与试验、数值模拟结果进行对比。结果表明：方钢管混凝土框架-十字加劲薄钢板剪力墙具有较高的水平承载力、初始刚度及良好的延性和耗能能力,水平承载力计算式的计算结果与试验、数值模拟结果吻合较好。     

Hybrid steel plate girders subjected to patch loading, Part 1: Numerical study

Extensive research focused on the structural behavior of hybrid steel plate girders is nowadays available in the literature. Furthermore, extensive research devoted to the resistance of homogeneous girders to patch loading has been performed in the last decades. Investigations dealing simultaneously with both fields are, however, rather scarce. The driving force behind developing the present research work has been the aim of completing the knowledge of the patch loading field for the particular structural alternative of hybrid steel plate girder. In the current paper, experimental results found in the literature as well as additional numerical simulations developed by the authors are summarized. The results presented can be used for assessing the resistance of hybrid steel plate girders subjected to patch loading. An in-depth exploit of such results is presented in a companion paper.     

Shear capacity of steel plate girders with large web openings, Part I: Modeling and simulations

Numerical simulations are carried out in order to provide data for the development of a design model for the shear capacity of steel girders with web openings, with and without transverse stiffeners and opening reinforcements. The numerical model is designed such that the girder is in a state of pure shear at the opening center. Results are presented in terms of ultimate shear capacity and distribution of transverse web deformations and von Mises stresses. Based on the numerical data, a design model is presented that accounts for the reduction in web shear area, shear buckling of the web and the effect of opening position, vertical stiffeners and opening reinforcements.     

Design of rectangular industrial duct plates subjected to out-of-plane pressure considering nonlinear large deformations

Large industrial steel ducts are often rectangular and are built-up of stiffened plates. The plates along with stiffeners act to resist the pressure loads and transfer these loads to the supports. Parallel wide flange steel profiles, usually beams, are used as transverse stiffeners that are spaced perpendicular to the longitudinal axis of duct. The design process involves determining the load carrying capacity and deflection of the plate based on the plate thickness and the spacing between stiffeners. The current analysis and design method for industrial ducts is based on the elastic large deflection plate theory using standard tables.A nonlinear finite element parametric study was conducted on dimensionless parameters to investigate the behavior of laterally loaded long plates. Through-thickness yielding of the plate and formation of partial plastic hinges at the ends is allowed. The results are presented in terms of a proposed dimensionless Normalized Load Factor (NLF) representing the applied pressure, the Normalized Deflection Factor (NDF) representing the out-of-plane deflection and the Normalized Maximum Stress Factor (NMSF) representing the maximum stresses induced in the plates. Design equations for deflection and stresses of plates are established with the aid of Bezier curves. A simple design procedure allowing for large deflection and partial yielding of edges is proposed. A limiting value for pressure has been found where it becomes irrelevant to check deflection. Results show that the proposed design procedure is simple and can lead to economic plate thicknesses and spacing of stiffeners in industrial ducts in ambient temperatures.     

Experimental and theoretical studies of steel shear walls with and without stiffeners

Steel plate shear walls are lateral load resisting systems, especially against earthquake excitation. They are constructed with or without stiffeners. In contrary to stiffened steel plate shear walls, there are many theoretical and experimental studies on these systems without stiffeners and different analytical methods have been presented for them which are mostly applicable to very thin steel plates shear walls. In this research, two one story similar steel plate shear walls with and without stiffeners and one of their surrounding frames were tested and the behavior of them was studied. The results showed that, installation of stiffeners improved the behavior of the steel plate shear walls. It caused 26% increase in energy dissipation capacity and 51.1% increase in the shear stiffness of steel plate while its effect on the steel plate shear strength was minor. In addition, the Plate-Frame interaction theory (PFI) was verified by using the experimental results and the test results showed that, this theory has good capability for predicting the shear load – displacement curve behavior of steel shear walls with or without stiffeners.     

加劲与不加劲钢板剪力墙的试验研究和理论分析

带或不带加劲肋的钢板剪力墙系统主要用于抵抗水平荷载,尤其是地震作用。现有文献对不带加劲肋的钢板剪力墙进行了大量的理论分析和试验研究,并提出了多种适用于超薄钢板剪力墙的分析方法,但对带加劲肋的钢板剪力墙研究较少。对2个带和不带加劲肋的单肢钢板剪力墙和其中的1榀外框架进行试验。结果表明,加劲肋提高了钢板剪力墙的性能,使钢板的能量耗散能力增加26%、剪切刚度增加51.1%,而对钢板的剪切强度影响甚微。此外,利用试验结果验证剪力墙-框架相互作用理论(PFI)的可行性。试验结果表明,该理论能够用于预测带或不带加劲钢板剪力墙剪切时的荷载-位移曲线。     

Analytical demonstrations to assess residual bearing capacities of steel plate girder ends with stiffeners damaged by corrosion

Many field surveys depict that steel plate girder ends tend to corrode due to the leakage of water from construction joints and/or detention of rain water near bearing regions. In many cases, buckling failures of plate girders were observed due to the excessive loss of material at the bottom portion of bearing stiffeners. In this study, the effect on the buckling strength of steel plate girder due to the corrosion damage at bearing stiffeners was investigated. Full-scale experimental tests were performed on two plate girder ends to determine the bearing capacity. Bearing capacity and failure modes were also verified by numerical analyses. Initial imperfections and welding residual stresses were also taken into account in analytical models. The simulation of the model was extended to the various corrosion damages, considering different damaged heights and thicknesses of the bearing stiffener near weld seam. All results were plotted in terms of remaining bearing capacity versus damage thickness ratio keeping the damage height of the stiffener constant. In this study, a damage parameter Reduced Thickness Ratio was used to assess the ultimate capacity and buckling of steel plate girder end with various corrosion levels.     

Experimental behaviour of a thermally restrained plate girder loaded in shear at elevated temperature

This paper outlines an experimental investigation of twelve simply supported steel plate girders subjected to shear loading at elevated temperature. Three different series of steel plate girders have been tested at three constant elevated temperature levels. Additional axial restraints were applied onto beams to simulate the thermal restraint effects of adjacent cooler parts of steel-framed structure in fire. Based on test results and observations, the pre- and post-buckling behaviours of plate girder web panels at high temperature were discussed. In addition, finite element modelling of the web panels was conducted and numerical models generally agreed well with test results. It was observed that the ultimate shear capacity decreased significantly under a thermal restraint effect.     

Ultimate load behaviour of webs in steel–concrete composite plate girders

The paper is concerned with the tension field action in webs of steel–concrete composite plate girders. A three-dimensional finite element model has been used to carry out nonlinear analyses on composite plate girders. The results obtained from the finite element analyses are compared with those from experiments. It is observed from the comparative study that the proposed nonlinear finite element model is capable of predicting the ultimate load behaviour of steel–concrete composite plate girders to an acceptable accuracy. Results are presented to explain the development of the tension field action in the webs and to illustrate a measure of the contribution by the concrete slab acting compositely with the girder to the changes in tension field compared to a plain steel girder.