Stainless Steel Plate Girders Research Articles

Shear response of lean duplex stainless steel plate girders

Carbon steel plate girders have been used on a large scale in the building industry. Nowadays, Lean Duplex Stainless Steel (LDSS) plate girders are gaining popularity as they possess greater strength and are more impervious to corrosion than those that are constructed from carbon steel. Regardless of their popularity, there is very limited information with regards to their shear behavior. In this paper, the non-linear finite element analysis was employed to investigate the shear behavior of LDSS plate girders. Parameters considered were the web thickness, the flange width, and the girders aspect ratio. The analysis revealed that although the shear behavior of the LDSS girders was no different from that of carbon steel plate girders, it had obviously been affected by the non-linearity of the material. Furthermore, the selected parameters were found to pronounce effect on the shear capacity of the LDSS girders. That is, the shear capacity increased considerably with web thickness, and increased slightly with flange width. However, it was reduced as the aspect ratio increased. Comparisons between the finite element analysis failure loads and those predicted by the current European Code of Practice revealed that the latter underestimated the shear strength of the LDSS plate girders.

Shear design recommendations for stainless steel plate girders

The behaviour and design of stainless steel plate girders loaded in shear is investigated in this paper. A review of existing methods for the design of stainless steel plate girders, including codified provisions, is first presented. A database of thirty-four experiments carried out on austenitic, duplex and lean duplex stainless steel plate girders is then reported, and used to assess the current shear resistance design equations from Eurocode 3: Part 1.4 and Eurocode 3: Part 1.5 and the recent proposals from the literature. The comparisons clearly indicate that the design provisions of Eurocode 3: Part 1.4 are conservative and that improved results can be achieved by applying Eurocode 3: Part 1.5 and the proposed expressions of Estrada et al. However, yet further improvements are possible and, based on the available structural performance data, revised design expressions for the calculation of the ultimate shear capacity of stainless steel plate girders suitable for incorporation into future revisions of Eurocode 3: Part 1.4 have been proposed and statistically verified. Unlike the current provisions of Eurocode 3: Part 1.4, the design rules proposed herein differentiate between rigid and non-rigid end posts, and, offer enhancements in shear buckling capacity of around 10%.

Flexural behavior of lean duplex stainless steel girders with slender unstiffened webs

The behavior of lean duplex stainless steel plate girders (LDIPGs) with slender unstiffened webs is studied in this paper. Firstly, shell finite element models are validated using experimental test results available in the literature. Secondly, these models are used to investigate the behavior of LDIPGs subjected to uniform bending. Parametric studies for the LDIPGs are carefully designed based on three parameters: the radius of gyration of the compression flange (rT), the section modulus (Sx), and the unbraced length (Lb). The results showed that LDIPGs with higher rT but similar Sx values can attain higher flexural strengths compared to their yield strengths because of the higher torsional rigidity of the flanges and stockier webs. On the other hand, by increasing the Sx value of the girder but keeping fixed the rT values, the moment carried by the girder is found relatively to decrease with the simultaneous increase in the amount of steel. Finally, the numerical results are compared with predictions given by design standards. It is found that the EC3 provides conservative bending predictions. Accordingly, the imperfection factor associated to buckling curve (c) is recommended to be used in the scope of the design method provided by EN 1993-1-4.

Buckling capacity of welded stainless steel flanges by finite element analysis

This paper presents the development of a finite element analysis method to predict the buckling capacity of welded stainless steel unstiffened plates. Material and geometric nonlinearities, geometric imperfections, and residual stresses are included in the development. The resulting method is validated with experimental results on specimens of cruciform shape and is used to measure the sensitivity of the compressive capacity of plates, whose boundary conditions simulate the flanges of stainless steel plate girders, to local geometric imperfection, length-to-width ratio, and slenderness. When the slenderness parameter of a flange is greater than 1.0, as the mode value of the imperfection increases, the compressive capacity increases, and when the slenderness parameter is less than 0.5 the mode value has negligible effect on the compressive capacity. When a flange length, a, is less than twice its width, b, the value of a/b has a much greater impact on the ultimate load capacity of the flange than when it is greater than twice its width. The parametric study results are compared to American, European, and Japanese design specifications for unstiffened steel cross-sectional elements. For a given value of slenderness, the AISC nominal design buckling resistance is close to the average of the ultimate loads obtained from the parametric study and the Eurocode and JSSHB specifications are generally conservative.

Experimental study of the shear response of lean duplex stainless steel plate girders

An experimental and numerical study of the shear response of lean duplex stainless steel plate girders is described in this paper. A total of nine welded plate girders were tested. Lean duplex stainless steel, which is a low nickel variety of the material, has approximately twice the strength of the common austenitic grades and at approximately half the initial cost. It also possesses good corrosion resistance and high temperature properties, as well as adequate weldability and fracture toughness. Two web panel aspect ratios and a range of web slendernesses were considered. The results from the experiments, including the full load-deformation histories and failure models are reported. A numerical investigation was carried out in parallel with the testing. The models were first validated against the experimental results after which parametric studies were performed to generate data for a wider range of cross-sections. The generated experimental and numerical data were used to assess the shear resistance design equations given in Eurocode 3: Part 1.4. The current design provisions were shown to be safely applicable to lean duplex stainless steel, though improved guidance is sought in further ongoing research.

Finite element investigation of shear failure of lean duplex stainless steel plate girders

The use of duplex stainless steel material has gained popularity in the last two decades thanks to its nature that combines well the advantages of both austenitics and carbon steel materials. The duplex grades offer a combination of higher strength than austenitics in addition to a great majority of carbon steels with similar or superior corrosion resistance. However, high nickel prices have more recently led to a demand for lean duplexes with low nickel content, such as grade EN 1.4162. Wide-ranging work is needed to include the lean duplex grade EN 1.4162, into design standards such as EN 1993-1-4. Accordingly, a finite element modelling for full-size lean duplex stainless steel plate girders of non-rigid end stiffeners of Grade EN 1.4162 is presented in this paper. The paper is principally concerned with shear failure mechanism characteristics of this type of plate girders, which is not yet investigated. The ABAQUS 6.6 programme, as a finite element package, is used in the current work. The lean duplex stainless steel material is simulated here based on an accepted stainless steel material model available in the literature. A number of transversely stiffened I-section plate girders having equal depth of 1000 mm in span of 4 m is considered and parametric studies regarding flange width-to-web depth ratio, flange-to-web thickness ratio and web plate slenderness are carried out. However, new conclusions on shear strength of lean duplex stainless steel plate girders are presented.

Imperfection analysis of austenitic stainless steel plate girders failing by shear

The austenitic grades nowadays feature most significantly within the constructional industry. Accordingly, the current paper is concerned with shear failure mechanism characteristics of this type of plate girder, which has not been completely investigated. An imperfection finite element analysis for complete austenitic stainless steel plate girders of grade EN 1.4301 (304) is conducted herein by using the ABAQUS 6.6 program. Two different initial imperfection magnitudes of h w / 100 000 and h w / 100 are included in the model, where h w denotes the web-depth of the plate girders. An arbitrary small initial imperfection value of h w / 100 000 is incorporated in an attempt to determine a bifurcation-type buckling load. h w / 100 is the maximum value allowed by the Bridge Welding Code (AASHTO/AWS 2002). The austenitic stainless steel material is simulated herein based on the two-stage full-range stress–strain material curve introduced by Rasmussen. Fifty eight I-shaped austenitic stainless steel plate girders, which are transversely stiffened and having an equal depth of 1000 mm in a span of 4 m, are considered and parametric studies vis-à-vis flange width-to-web depth ratio, flange-to-web thickness ratio and web plate slenderness are carried out. The results of the finite element modelling showed, generally, that the design equations specified by the European specifications are conservative for the design of austenitic stainless steel plate girders of the maximum imperfection amplitude; h w / 100 . At the end, an adjustment is made to the European specifications that is accurately found to represent the behavior of the austenitic stainless steel plate girders better than the existing equations.

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.

A new developed expression to determine more realistically the shear buckling stress in steel plate structures

This paper summarises and presents main results of an in-depth numerical analysis dealing with the shear buckling resistance of stainless steel plate girders. The studies conducted have permitted the development of a simple design expression to determine the critical shear buckling stress in steel web panels. This expression takes into account the effects of the material nonlinearity together with the actual boundary conditions of the web panel given by the geometry of the plate girder by two defined parameters: η and k rss , which is the shear buckling coefficient. Expressions given to obtain η will quantify mainly the effect of the material nonlinearity whereas the proposed analytical expression of k rss will reproduce principally the influence of the real boundary conditions in a web panel.

General behaviour and effect of rigid and non-rigid end post in stainless steel plate girders loaded in shear. Part II: Extended numerical study and design proposal

After the deep analysis and evaluation of the experimental and numerical results obtained during the described experimental campaign [Estrada I, Real E, Mirambell E. General behaviour and effect of rigid and non-rigid end post in stainless steel plate girders loaded in shear. Part I: Experimental study. Journal of Constructional Steel Research 2005 [submitted for publication]], an extended numerical analysis in code ABAQUS [Hibbit, Karlsson and Sorensen Inc., ABAQUS/Standard, Version 6.3. User’s manual. Rhode Island (USA); 2002] has been carried out dealing with the evaluation of the postbuckling strength in stainless steel plate girders. Finally, a proposal of design expressions for predicting their ultimate shear capacity is made since current design specifications dealing with shear resistance included in Eurocode 3, Part 1–4 [European Committee for Standardisation. ENV 1993-1–4. Eurocode 3: Design of steel structures. Part 1.4: General rules—supplementary rules for stainless steel. Brussels; 1996] have been demonstrated to be overly conservative. Taking special attention of the material non-linearity and the rigid or non-rigid condition of the end post, specimens covering a wide range of slenderness and aspect ratios ( a / d from 0.5 to 3.0) have been numerically tested. Austenitic and Duplex stainless steel grades, which are the most commonly used in construction, have been evaluated during the whole analysis development. Finally, a new design proposal based on the Rotated Stress Field model developed by Höglund [Höglund T. Shear buckling resistance of steel and aluminium plate girders. Thin-Walled Structures 1998;29(1–4):13–30], adequately adapted to the particular features of stainless steel is presented in order to reach a more optimum use of this relatively modern resistant material in construction.

General behaviour and effect of rigid and non-rigid end post in stainless steel plate girders loaded in shear. Part I: Experimental study

To better understand the response of stainless steel plate girders loaded in shear, an experimental campaign was carried out at UPC as a part of extensive research on shear behaviour of stainless steel girders. A total of 8 stainless steel plate girders were tested. The primary design variables were, apart from the aspect ratio and slenderness of the web panel, the rigid or non-rigid condition of the end post. In parallel, a numerical model was developed in code ABAQUS [Hibbit, Karlsson and Sorensen Inc., ABAQUS/Standard, Version 6.3. User’s manual. Rhode Island (USA); 2002]. The tests results served as a basis for calibration of numerical models and furthermore for the development and verification of a new approach to structural stainless steel design. Different responses and modes of failure in shear were observed and special attention was taken of the effect of the rigidity of the end post during the analysis of results. The comparative analysis of the experimental results with current codes’ approaches clearly shows that shear design procedures included in Eurocode 3 Part 1.4 [European Committee for Standardisation. ENV 1993-1-4. Eurocode 3: Design of steel structures. Part 1.4: General rules—supplementary rules for stainless steel. Brussels; 1996], which specifically deals with stainless steel structures, are overly conservative.