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会议名称:

Structural Stability Research Council annual stability conference

召开年:

2016

召开地:

Orlando, FL

会议文集:

Structural Stability Research Council annual stability conference 2016: Structural Stability Research Council annual stability conference 2016, 12-15 April 2016, Orlando, Florida, USA

主办单位:

Structural Stability Research Council

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  • 题名 作者 来源 发表时间 操作
  • Local buckling limit states in rod-braced metal building frames

    作者:Hamid. Foroughi;Chengda. Ji;Benjamin W. Schafer;Christopher D. Moen; 会议名称:Structural Stability Research Council annual stability conference 2018年

    Flange local buckling in metal building primary frames can initiate as rod brace anchor loads are carried through the closest steel frame flange to a girt, purlin, or to flange bracing collectors. Anchor rods are typically placed eccentrically in a steel frame, adjacent to one flange of the built-up steel cross-section to limit local web deformation, and this eccentricity initiates weak axis bending and torsion that is accompanied by axial force from the rod inclination. An experimental program was conducted to study frame-anchor interaction and document strength limit states. One of these limit states was flange local buckling, which resulted in a sudden primary frame lateral stiffness reduction that was mitigated after buckling by high warping restraint provided by frame continuity, leading to a stiff post-buckling path at large lateral frame deformations. The experimental results inspired a primary frame structural model, developed with insight from thin-shell finite element simulations, that allows mapping of rod anchor forces to flange demand, critical elastic buckling, and yielding parameters that define flange slenderness. With this model in hand, possible approaches for calculating metal building primary frame capacity including flange local buckling are explored, and possible pathways for future research are identified.

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  • Local buckling limit states in rod-braced metal building frames

    Hamid. Foroughi;Chengda. Ji;Benjamin W. Schafer;Christopher D. Moen;

    Structural Stability Research Council annual stability conference

    2018年

  • Computational Study of Tension Field Action in Gable Frame Panel Zones

    作者:Gengrui Wei;Ioannis Koutromanos;Thomas M. Murray;Matthew R. Eatherton; 会议名称:Structural Stability Research Council annual stability conference 2018年

    Gable metal frames are popular, cost-efficient structural systems for commercial and industrial buildings. The use of relatively thin web material typically leads to buckling of the panel zone in the beam-to-column connections when the frame is subjected to lateral loads. However, the panel zones may still be capable of developing post-buckling resistance by means of tension field action (TFA). Previous experimental research has shown that the exterior corner of a panel zone in gable frame knee joints may not be stiff enough to fully develop TFA. Although these test results have demonstrated the development of post-buckling strength, the amount of TFA and the design parameters that affect such action are not well understood. This paper presents a theoretical model for TFA in knee joints based on plastic analysis, and an accompanying equation for predicting the post-buckling panel zone strength for positive bending (wherein the tension field is oriented from the interior to the exterior corners). The TFA was found to primarily depend on three design parameters, namely, flange flexural strength, panel aspect ratio, and panel slenderness. To calibrate the proposed equation, a parametric analytical study was conducted using the finite element method. The modeling scheme accounted for material and geometric nonlinearity and was validated with experimental test data. The study involved 98 prototype gable frame configurations and allowed the investigation of the impact of the aforementioned three design parameters on the TFA. The proposed equation was found to predict the panel zone shear strength for the prototype frames with an average error of 1 % and an error standard deviation of 5%. Therefore, the equation can be used to calculate the post-buckling shear strength of panel zones for the range of design parameters considered in the parametric study.

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  • Computational Study of Tension Field Action in Gable Frame Panel Zones

    Gengrui Wei;Ioannis Koutromanos;Thomas M. Murray;Matthew R. Eatherton;

    Structural Stability Research Council annual stability conference

    2018年

  • Horizontal Curvature Impacts on Steel Plate Girder Shear Buckling

    作者:Bernard A. Frankl;Daniel G. Linzell; 会议名称:Structural Stability Research Council annual stability conference 2018年

    Current provisions for shear design of slender, steel, plate girders do not account for effects from horizontal curvature, sometimes resulting in overly conservative designs. Excess transverse stiffeners are often specified and, since they are welded to the girder web, an increased risk of fatigue could exist. This manuscript summarizes a study that investigated horizontal curvature effects on shear behavior of steel plate girders having slender webs. Two shear buckling coefficients that include these effects are presented and compared against curved girder finite element models. Results show horizontal curvature increases shear buckling capacity and ultimate shear strength over a range of girder horizontal curvatures, web slenderness ratios and panel aspect ratios. These enhanced capacities could be utilized to reduce the number of transverse stiffeners needed to resist construction and service load demands.

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  • Horizontal Curvature Impacts on Steel Plate Girder Shear Buckling

    Bernard A. Frankl;Daniel G. Linzell;

    Structural Stability Research Council annual stability conference

    2018年

  • Flexural resistance of longitudinally stiffened curved I-girders

    作者:Lakshmi P. Subramanian;Donald W. White; 会议名称:Structural Stability Research Council annual stability conference 2018年

    The current AASHTO Specifications neglect the contribution of the longitudinal stiffeners to the flexural resistance of slender-web I-girders after the webs have undergone bend-buckling. The authors have previously developed a cross-section model to address this conservatism, and proposed a simplified equation to calculate the web bend-buckling factor Rb for straight longitudinally stiffened I-girders. The recommendations are shown to work well not only for the yield limit state, but also for members with lateral torsional buckling and flange local buckling as the controlling limit states. The model also works well for cases with high moment and high shear. Horizontally-curved girders experience larger flange lateral bending stresses due to curvature, and the Specifications treat the compression flanges of such members as equivalent beam-columns. The current paper examines whether the proposed modified equations for Rb developed based on straight longitudinally stiffened girders can be applied to horizontally curved longitudinally stiffened I-girders within the framework of the current beam-column type equations (termed as the l/3rd rule). The paper first illustrates that the design of curved longitudinally stiffened girders is always limited to either the yield limit state or the shorter lengths in the inelastic LTB region. The paper also recommends an increase in the curvature parameter, Z from the current value of 10 to 13 using finite element simulations on homogeneous I-girders subjected to uniform moment.

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  • Flexural resistance of longitudinally stiffened curved I-girders

    Lakshmi P. Subramanian;Donald W. White;

    Structural Stability Research Council annual stability conference

    2018年

  • Experimental Study on the Interaction of Partial Top Lateral and K-Frame Bracing on Tub Girders

    作者:Stalin Armijos Moya;Yang Wang;Todd Helwig;Michael Engelhardt;Patricia Clayton;Eric Williamson; 会议名称:Structural Stability Research Council annual stability conference 2018年

    Steel box girder systems, which consist of steel tub girders with a cast in-place concrete deck on top, are a popular alternative for straight and horizontally curved bridges due to their high torsional stiffness and aesthetic appearance. However, steel tub girders possess a relatively low torsional stiffness during transport, erection and construction because of the thin-walled open section. Additionally, during the casting of concrete, the upper portion the tub girder is in compression in the positive moment region and the girder is susceptible to lateral torsional buckling (LTB). Usually, top flange lateral bracing (TLB), in the form of a horizontal truss, is installed along the entire length of the steel tub girder to increase the torsional stiffness of the girder and to prevent LTB. However, for straight or nearly straight girders, the horizontal truss is mainly effective near the ends of the girders where the shear deformations are the largest. The contribution of the top lateral bracing to control lateral torsional buckling is notably reduced at the mid-span region. Also, internal K-frames are placed to control cross-sectional distortion. This paper provides an overview of on an ongoing research study focused on improving the efficiency of steel tub girders by investigating the impact of the girder geometry and bracing details on the behavior of the girders. The study includes large-scale experimental tests and parametric finite element analytical (FEA) studies. This paper highlights both the experimental tests and part of the analytical study. The interaction between partial top lateral and K-frame bracing systems is assessed by conducting multiple elastic-buckling tests on three steel tub girders with different amounts of top lateral bracing along the girder. Interaction between these two types of bracing systems was observed with variations in the forces of the top lateral truss diagonals and struts when the configuration of internal K-frames was altered. The three tub girder specimens were also subjected to vertical bending and combined bending and torsion using concentric and eccentric loads, respectively, applied by gravity load simulators. The goal of the study is to improve the efficiency of steel tub girders by optimizing the bracing while maintaining adequate safety.

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  • Experimental Study on the Interaction of Partial Top Lateral and K-Frame Bracing on Tub Girders

    Stalin Armijos Moya;Yang Wang;Todd Helwig;Michael Engelhardt;Patricia Clayton;Eric Williamson;

    Structural Stability Research Council annual stability conference

    2018年

  • Improved Characterization of the Flexural and Axial Compressive Resistance of Noncomposite Longitudinally Stiffened Welded Steel Box-Section Members

    作者:Ajinkya M. Lokhande;Donald W. White;Charles M. King;Michael A. Grubb; 会议名称:Structural Stability Research Council annual stability conference 2018年

    There exists great potential for improvement of existing methods for calculating the flexural and axial compressive resistance of longitudinally stiffened welded steel box-section members, to achieve gains in the accuracy of their representation of the limit states responses as well as greater generality and ease of their design application. A good quantification of the ultimate compressive resistance of longitudinally stiffened plates is crucial for accurate characterization of the flexural and axial compressive resistance of these member types. This paper summarizes the conceptual and theoretical development of new methods for characterization of the ultimate compressive resistance of longitudinally stiffened plates, and the flexural and axial compressive resistance of longitudinally stiffened welded box-section members. The proposed method for calculating the plate compressive resistance is derived using an orthotropic plate idealization, but is expressed as a designer-friendly, intuitive column on elastic foundation model. This model considers the contributions from longitudinal stiffener flexure, transverse plate bending, and plate torsion. The proposed method for calculating member flexural resistance recognizes the inability of longitudinally stiffened flange plates to sustain large inelastic compressive strains beyond their maximum resistance, and therefore limits the flexural resistance of box sections with a longitudinally stiffened compression flange to the first yield of the compression flange in the effective cross-section. For sections involving early yielding of the tension flange, the member response is addressed rigorously via the direct calculation of the yield moment to the compression flange, considering the early yielding on the tension side of the neutral axis, and considering hybrid web, slender web and unstiffened slender or longitudinally stiffened compression flange effects as applicable. The paper presents a parametric study of longitudinally stiffened welded box columns whose failure mode involves combined flexural and local buckling, for which there is no experimental or finite element simulation data in the literature. The predictions using the proposed methods correlate well with the results from finite element test simulations, and with data compiled from experimental tests.

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  • Improved Characterization of the Flexural and Axial Compressive Resistance of Noncomposite Longitudinally Stiffened Welded Steel Box-Section Members

    Ajinkya M. Lokhande;Donald W. White;Charles M. King;Michael A. Grubb;

    Structural Stability Research Council annual stability conference

    2018年

  • Seismic Performance Evaluation of Cold-Formed Steel Framed Shear Walls using In-Frame Corrugated Steel Sheets

    作者:Xing Lan;Wenying Zhang;Mahsa Mahdavian;Cheng Yu; 会议名称:Structural Stability Research Council annual stability conference 2018年

    This paper presents experiments and finite element analysis of an innovative cold-formed steel framed shear wall with corrugated steel sheathing. The novel shear wall is high strength, non-combustible, and is equal in width with adjacent walls. Full-scale monotonic and cyclic tests were conducted on bearing walls and shear walls under combined lateral and gravity loading. The strength of the novel shear wall is higher than currently code certified shear walls in AISI S400-15 so that it could be employed for mid-rise buildings in areas that are prone to high seismic and wind loads. It was also found that the shear strength of bearing wall was approximately one third of the shear strength of shear wall, which proves that bearing walls provide significant shear resistance in a structure. In finite element analysis, shear wall models were first simulated and verified in OpenSees software, then nonlinear static and dynamic analysis were performed in OpenSees software according to the methodology recommended by FEMA P695. The objective of numerical analysis was to evaluate and quantify seismic performance factors of this new lateral force resisting system. The seismic performance evaluation results verified that the existing seismic performance factors for conventional light framed shear wall systems were appropriate for the novel cold-formed steel shear wall systems.

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  • Seismic Performance Evaluation of Cold-Formed Steel Framed Shear Walls using In-Frame Corrugated Steel Sheets

    Xing Lan;Wenying Zhang;Mahsa Mahdavian;Cheng Yu;

    Structural Stability Research Council annual stability conference

    2018年

  • Evaluation of Seismic Design Methods for Steel Multi-Tiered Special Concentrically Braced Frames

    作者:Pablo A. Cano;Ali Imanpour; 会议名称:Structural Stability Research Council annual stability conference 2018年

    Steel Multi-Tiered Concentrically Braced Frames (MT-CBFs) are commonly used in North America as a lateral load-resisting system of tall single-story buildings. Multi-Tiered configurations are typically used when a single braced panel between the roof and ground levels is impractical in the case of tall building. Past studies show that MT-CBF columns designed in accordance with the 2010 US Seismic Provisions are prone to buckling due to a high axial compression force and in-plane bending demands induced in columns as a result of non-uniform distribution of brace inelastic deformations along the frame height. Special design provisions have been introduced in the current US Seismic Provisions to address flexural demands imposed on MT-CBF columns and prevent column instability. Nevertheless, the recent improvements lack full-scale experimental testing and comprehensive finite element simulations featuring current guidelines. In this study, the seismic design methods for Multi-Tiered Special Concentrically Braced Frames are evaluated using the nonlinear finite element method. First, a two-tiered SCBF was designed in accordance with the 2010 and 2016 requirements. A detailed finite element model of the frames was then created and a non-linear cyclic-pushover analysis was performed to evaluate the seismic performance of both frames. Special attention was paid to the validation of the design forces prescribed in the 2016 Seismic Provisions. Analyses results confirmed that the inelastic deformations in the frame designed using the 2010 requirements are not uniformly distributed but rather concentrated in one of the tiers; whereas, the current design method significantly reduces the concentration of inelastic deformations in a single tier and prevents column instability. Furthermore, it was found that column in-plane flexural demands are overestimated when designed in accordance with the current provisions. Further numerical simulations on a large number of frame configurations using the dynamic response history analysis procedure are required to verify this observation.

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  • Evaluation of Seismic Design Methods for Steel Multi-Tiered Special Concentrically Braced Frames

    Pablo A. Cano;Ali Imanpour;

    Structural Stability Research Council annual stability conference

    2018年

  • Development of a computational model to estimate the rollover resistance of open web steel joist seats

    作者:Jean C. Batista Abreu;Ronald D. Ziemian; 会议名称:Structural Stability Research Council annual stability conference 2018年

    Joist seats play a critical role in the performance of open web steel joist systems because they transfer loads from the floor or roof deck to the end supporting girders or walls. The strength of these seats might be controlled by local sides-way instability or "rollover" when they are subjected to the combination of gravity and lateral loads. The current objective of this research is to develop and utilize a nonlinear finite element model to predict the stiffness and strength of typical steel joist seat configurations subjected to forces that produce local sides-way instability. The configurations studied include lapped and three-plate welded joist seats. Numerical results are validated against experimental data documented in the literature. Findings indicate that three-dimensional nonlinear finite element models are capable of estimating the response of laterally loaded steel joist seats, and also demonstrate that the strength and stiffness of joist seats strongly depend on the seat configuration. In addition, these models show how the load is transmitted to the supports through the seats, and indicate the development of plastic zones as the seats deform. Future work includes preparing a parametric study to investigate the impact of design variables, including dimensions, configuration type and material properties, on the rollover resistance of open web joist seats with welded and bolted connections. Currently, the design of some joist seats can be completed by means of elastic or plastic mechanism approaches. Therefore, this study aims to generate more comprehensive design recommendations and guidelines to determine the rollover capacity of such seats.

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  • Development of a computational model to estimate the rollover resistance of open web steel joist seats

    Jean C. Batista Abreu;Ronald D. Ziemian;

    Structural Stability Research Council annual stability conference

    2018年

  • Ten years of research on stability of thin-walled members revisited

    作者:Rodrigo M. Goncalves; 会议名称:Structural Stability Research Council annual stability conference 2018年

    This paper corresponds to the text version of the presentation delivered on April 11, 2018, at the SSRC Annual Stability Conference, in the context of the 2017 SSRC McGuire Award for Junior Researchers. The paper reviews the most relevant research in which the author has been involved, in the topic of stability of thin-walled members and held in the past ten years. In particular, the paper addresses three main areas: Generalized Beam Theory, geometrically exact beam formulations and structural design aspects.

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  • Ten years of research on stability of thin-walled members revisited

    Rodrigo M. Goncalves;

    Structural Stability Research Council annual stability conference

    2018年

  • Tests on bolted steel angles in compression with varying end support conditions

    作者:Markus Kettler;Gerit Lichtl;Harald Unterweger; 会议名称:Structural Stability Research Council annual stability conference 2018年

    Structural steel angles are often used as bracing members in buildings or in lattice transmission towers. Bolted end-connections of single steel angles allow for easy fabrication and quick erection, but induce additional bending moments due to the eccentric load introduction. This leads to a complex load carrying behavior, especially for members in compression. This causes a decrease in capacity compared to the case of a simply supported column with centric loading for smaller slenderness ratios. For larger slenderness ratios the beneficial effect of end restraints is assumed to compensate this drawback. Current design standards account for these effects via modified effective slenderness ratios resulting in significantly different predictions for the member capacities according to the individual regulations.

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  • Tests on bolted steel angles in compression with varying end support conditions

    Markus Kettler;Gerit Lichtl;Harald Unterweger;

    Structural Stability Research Council annual stability conference

    2018年

  • Stability Considerations for Concrete Forming Support Systems

    作者:Cliff D. Bishop;William Trono;Morgan Griffith; 会议名称:Structural Stability Research Council annual stability conference 2018年

    The contractual responsibilities of building designers are often limited to the performance of a structure after construction is complete. That is, the designers leave the means and methods of construction, including the stability of the partially completed structure, to the contractor. This can lead to problems, as contractors are likely not trained in structural stability and may not understand how seemingly minor alterations to components can have a disproportionate effect on the stability of the temporary works. This paper presents a case study that explores the stability of shoring systems used to support concrete formwork, and in particular the adverse effects of modifying component lengths and the addition of aluminum spacers. Classical calculations are performed and verified using OpenSees analyses to determine the expected change in capacity due to the adjustments. Finally, we offer advice to engineers and contractors warning of dangerous adjustments so they might avoid similar damage or collapse of forming support systems on their projects.

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  • Stability Considerations for Concrete Forming Support Systems

    Cliff D. Bishop;William Trono;Morgan Griffith;

    Structural Stability Research Council annual stability conference

    2018年

  • Load Tests of Common Shoring Towers: Typical Detailing and Resulting Capacity Reduction

    作者:Aaron K. Larosche;Stalin Armijos M;Keaton E. Munsterman;Todd A. Helwig;Michael D. Engelhardt;Randall W. Poston; 会议名称:Structural Stability Research Council annual stability conference 2018年

    Following an in service collapse, three shoring towers were tested to failure at the University of Texas at Austin's Ferguson Structural Engineering Laboratory (FSEL) to better understand the cause of the collapse. Both numerical analyses and experimental results indicated a stability limit state governed the load capacity that may have not be adequately considered in the design of the shoring towers. The shoring system tested is widely used in construction and is constructed of modular aluminum components. A typical four-leg tower is constructed with paired frame segments, each containing two column legs. Frame segments are stacked and fitted with adjustable height extensions. Tower legs support a system of cribbage that includes beams and girders, which in turn support wooden formwork. The detail of placing a beam or girder directly over a column is known to increase the effective length of the supporting column, thereby reducing its buckling capacity. A number of structural collapses over many years have been attributed to this destabilizing detail. Consequently, the detail is typically either avoided or is modified to minimize its destabilizing effects. The shoring system tested includes the destabilizing beam-over-column detail without modification. To investigate the effects of the detail on the capacity of a shore tower, tests performed at FSEL included specimens with and without the beam-over-column detail. The first test, of three, applied load directly to the legs of a four-leg tower, and did not include the destabilizing beam-over-column detail. A buckling failure occurred at 96% of the manufacturers' provided ultimate load. The second and third tests included the beam-over-column detail and were loaded through wooden formwork and a cribbage system, to be representative of typical field conditions. The results of these tests, which included the detail discussed, showed an approximate reduction in ultimate load of 40% prior to failure.

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  • Load Tests of Common Shoring Towers: Typical Detailing and Resulting Capacity Reduction

    Aaron K. Larosche;Stalin Armijos M;Keaton E. Munsterman;Todd A. Helwig;Michael D. Engelhardt;Randall W. Poston;

    Structural Stability Research Council annual stability conference

    2018年

  • Direct Strength Approach to Predict the Flexural Strength of Cold-Formed Z-Section Purlins on Sloped Roofs

    作者:Ali Parva;Michael W Seek; 会议名称:Structural Stability Research Council annual stability conference 2018年

    In this study, the strength of cold-formed Z-section purlins is predicted considering the effects of roof slope in real roof systems. The study applies to simple span purlins with torsion restraints at support locations and at paired locations along the length of the member. A previously developed method has shown through comparisons to base tests that when the biaxial bending and torsion stresses are incorporated into the analysis, the Direct Strength Method can accurately predict the strength of a purlin. These stress distributions can deviate substantially from the constrained bending approximation typically assumed in analysis and therefore impacts the local and distortional buckling behavior. The method was modified to represent the system conditions in real roofs and to include roof slope. The base test is a test intended to represent real roof conditions, however second order stresses can be introduced as a result of the limitations of the test. Real roof systems are not subject to some of these second order effects. Similarly, as slope effects are included in the analysis, biaxial bending and torsion stresses can change significantly relative to the flat roof condition, particularly for flexible standing seam diaphragms. This change in stresses in turn changes the local and distortional buckling behavior of the purlin. Initially, for low slope roofs, the predicted strength increases relative to the flat roof condition. As the roof slope increases and the mid-span of the purlin displaces downslope, the flexural strength of the purlin can be less than the flat roof condition. Using the analytical model developed in this study, the strength of purlins is evaluated at different roof slopes and compared to the "real" flat roof condition.

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  • Direct Strength Approach to Predict the Flexural Strength of Cold-Formed Z-Section Purlins on Sloped Roofs

    Ali Parva;Michael W Seek;

    Structural Stability Research Council annual stability conference

    2018年

  • Signature curve for general thin-walled members

    作者:Sandor Adany; 会议名称:Structural Stability Research Council annual stability conference 2018年

    Signature curve is widely used in stability design of cold-formed steel members, since it provides with a simple way to determine critical loads for local, distortional and global buckling, which then can be used in predicting member capacity. Signature curve is created by calculating critical loads by systematically changing the length of the thin-walled member while assuming that the load is uniform along the length and the transverse displacement is one single sine half-wave. Mathematically, these conditions are closely related to the semi-analytical finite strip method, while, practically, correspond to a member with pinned end supports subjected to two concentrated loads at the ends, equal in magnitude but opposite in direction. This definition of signature curve cannot easily be applied to more general cases, however, a possible generalization is presented in the paper. Numerical examples are also shown, by employing the constrained finite element method. If the proposed procedure is applied for basic members, the calculated generalized signature curve exactly coincides with the classic signature curve. It is also shown, however, that meaningful generalized signature curve can be calculated for various loading and supports, or even for members with holes.

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  • Signature curve for general thin-walled members

    Sandor Adany;

    Structural Stability Research Council annual stability conference

    2018年

  • Modeling the Influence of Residual Stress on the Ultimate Load Conditions of Steel Frames

    作者:Barry T. Rosson; 会议名称:Structural Stability Research Council annual stability conference 2018年

    A generalized material model for wide-flange sections was developed based on m-p-τ plots of detailed fiber element models over a full range of moment, axial load and maximum residual stress conditions. Several different cross-sections were investigated to determine the appropriate exponent in the material model for approximating the stiffness reduction under major axis bending or minor axis bending conditions. The nonlinear material model was used as normalized tangent modulus expressions in MASTAN2 and ultimate load analyses were conducted on four benchmark frames. Using residual stress scale factor conditions of 0.6 and 1.4, the relative percent difference in the lateral load at collapse was investigated as the initial vertical load conditions were increased. The influence of residual stress was studied on three test frames with loads applied only at the beam-to-column joints and on one test frame with more realistic design conditions. Discussion is provided on the ability of the material model to approximate the stiffness reduction of wide-flange sections and on the conditions that produce an increased residual stress effect on the ultimate load capacity of steel frames.

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  • Modeling the Influence of Residual Stress on the Ultimate Load Conditions of Steel Frames

    Barry T. Rosson;

    Structural Stability Research Council annual stability conference

    2018年

  • Shear Resistance Mechanisms of Steel Sheet Walls with Burring Holes and the Effect of Wall Widths with Vertical Slits

    作者:Yoshimichi Kawai;Kazunori Fujihashi;Shigeaki Tohnai;Atsushi Sato;Tetsuro Ono; 会议名称:Structural Stability Research Council annual stability conference 2018年

    Shear walls containing 2.73-m-long × 0.455-m-wide steel sheets with vertically aligned burring holes are employed in multi-story buildings in seismically active regions. A configuration with burrs on the inside enables the construction of thinner walls and simplified attachment of finishing. The machining of equipment and piping holes at the construction site can be omitted by the holes. In-line 1.82-, 2.73-, and 3.64-m-wide walls are employed in the buildings, with at least one vertical slit every 0.91-m-wide. The purpose of this study is to clarify the shear resistance mechanisms of walls with burring holes and the effects of wall widths with and without vertical slits. The wall that receives the in-plane shear force allows shear stress to concentrate in the intervals between the holes. Finite element analysis and shear experiments revealed that all intervals between the holes were simultaneously deformed and that the buckling areas in the intervals were restricted by the use of ring-shaped burring ribs of the holes. The postbuckling behavior was dependent on the shapes of the tension field on the intervals. The effect of vertical slits involved maintaining wall strength stable in the inelastic region. The formulas of the allowable design strength and the indexes of strength after shear buckling were developed.

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  • Shear Resistance Mechanisms of Steel Sheet Walls with Burring Holes and the Effect of Wall Widths with Vertical Slits

    Yoshimichi Kawai;Kazunori Fujihashi;Shigeaki Tohnai;Atsushi Sato;Tetsuro Ono;

    Structural Stability Research Council annual stability conference

    2018年

  • Distortional Failure and DSM Design of Cold-Formed Steel Lipped Channel Beams under Non-Uniform Bending

    作者:Isis Cler Depolli;Alexandre Landesmann;Dinar Camotim;Andre Dias Martins; 会议名称:Structural Stability Research Council annual stability conference 2018年

    Recently, Martins et al. (2017a) reported an in-depth numerical investigation that providing solid evidence that the current Direct Strength Method (DSM) beam distortional strength curve overestimates the ultimate strength of cold-formed steel simply supported beams, thus leading to unsafe designs - the beams analyzed were uniformly bent (mostly about the major-axis). Moreover, the above authors used the distortional failure moment data obtained to propose new DSM beam distortional design curves, differing visibly from the current one for moderate-to-high slenderness - these curves were already successfully employed in the context of the design of uniformly bent beams undergoing local-distortional interaction (Martins et al. 2017b). The work reported in this paper, which may be viewed as a continuation of the aforementioned investigation, concerns the distortional post-buckling behavior and DSM design of simply supported cold-formed steel beams buckling and failing in distortional modes under non-uniform bending due to unequal end moments - five bending moment diagrams (including uniform bending, for comparison purposes) are considered. As in previous studies, two beam simply supported end conditions are considered, differing in the end cross-section warping and local displacements/rotations, which may be either completely free or fully prevented. The beams analyzed buckle and fail in modes exhibiting various half-wave numbers. After acquiring in-depth insight on how the bending moment diagram influences the beam distortional buckling and post-buckling behaviors, an extensive numerical (shell finite element) parametric study is carried out in order to gather significant distortional failure moment data concerning lipped channel beams with various cross-section dimension ratios and yield stresses (to enable covering wide distortional slenderness ranges). These failure moments, together with additional values collected from the literature, are then employed to assess the merits of the available DSM beam distortional strength curves in predicting them, and also to propose slight adjustments/modifications aimed at achieving DSM design curves able to provide accurate failure moment predictions that take into account the variation of the bending moment diagram.

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  • Distortional Failure and DSM Design of Cold-Formed Steel Lipped Channel Beams under Non-Uniform Bending

    Isis Cler Depolli;Alexandre Landesmann;Dinar Camotim;Andre Dias Martins;

    Structural Stability Research Council annual stability conference

    2018年

  • Warping and Deformations in Profiled Steel Deck under Shear

    作者:Astrid W. Fischer;Guanbo Bian;Benjamin W. Schafer; 会议名称:Structural Stability Research Council annual stability conference 2018年

    The objective of this paper is to evaluate currently available methods for predicting the warping and other deformations that occur in bare steel deck profiles under shear. Profiled steel panels often serve as the diaphragm in single-story buildings and thus are the main element for distributing lateral forces to the walls. As a diaphragm they largely undergo in-plane shear. Thus, the in-plane shear stiffness of these panels is of crucial importance in design. The American Iron and Steel Institute (AISI) S310 Specification and Steel Deck Institute's Diaphragm Design Manual (DDM) provide an analytical approximation for determining the shear stiffness based on contributions from the deck in pure shear, connection slip, and warping of the deck. Due to the thin-walled nature of the deck geometric nonlinear deformations can be important and stability of the deck profile can also influence the stiffness results. The prediction of the warping deformations is based on a simplified two-dimensional beam on elastic foundation approximation that is explained in detail herein. This model is an approximation of the actual three-dimensional deformations. Shell finite element models are constructed in ABAQUS to examine the deck shear displacements and idealized boundary conditions are introduced to isolate the deck deformations and compare with the approximations in DDM/AISI S310. Comparison of the results indicates that improvements in the DDM/AISI S310 model for predicting warping are possible; as is generalization of the approximate method employed. Shell finite element predictions of pure shear stiffness and connection slip are found to be in good agreement with DDM/AISI S310. This work is part of the larger Steel Diaphragm Innovation Initiative and aims to understand and optimize the behavior of steel deck diaphragms.

    关键字:

  • Warping and Deformations in Profiled Steel Deck under Shear

    Astrid W. Fischer;Guanbo Bian;Benjamin W. Schafer;

    Structural Stability Research Council annual stability conference

    2018年

  • Application of the direct strength method to functionally-'raded-material-sheathed cold-formed steel beam channel members under nonuniform elevated temperature

    作者:Elias Y. Ali;Yared Shifferaw; 会议名称:Structural Stability Research Council annual stability conference 2018年

    The objective of this paper is to examine the application of the Direct Strength Method (DSM) to determine the strength of cold-formed steel (CFS) beam channel members under non-uniform elevated temperature using Functionally Graded Material (FGM) as a thermal barrier. Functionally graded materials are advanced materials characterized by non-homogenous material system with gradual gradation of material property within a given dimension. The composition of the FGM sheathing is defined by using the volume fractions of the constituent materials distributed across the thickness direction. When a cold-formed steel member is subjected to fire (or a thermal gradient) on one side of the panel, material properties change - but this change happens around the cross-section and along the length creating a member which is potentially non-uniform and unsymmetrical in its response even if the apparent geometry is uniform and symmetric. The heat transfer analysis is completed using ABAQUS to obtain the time-dependent temperature distribution on the CFS cross-sections. The influence of sheathing material on the response of the members is compared with the strength of same sections with gypsum board as a thermal barrier. DSM strength formulations are examined following stability analyses performed to characterize how local, distortional, and global buckling of the members evolve under elevated temperature, in which mechanical properties are considered temperature dependent.

    关键字:

  • Application of the direct strength method to functionally-'raded-material-sheathed cold-formed steel beam channel members under nonuniform elevated temperature

    Elias Y. Ali;Yared Shifferaw;

    Structural Stability Research Council annual stability conference

    2018年

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