Collapse Response and Design of Deep Steel Columns Subjected to Lateral Displacement

Fogarty, J.; Wu, Tsung-Tsong; El‐Tawil, Sherif

doi:10.1061/(asce)st.1943-541x.0001848

Cited by 20 publications

(6 citation statements)

References 6 publications

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“…In this context, it was found that the member slenderness Lb/ry is somewhat important but only at story drift ratios larger than 3%. Depending on the employed performance objective criteria, alternative expressions may be used for the same purpose such as those proposed by Fogarty et al (2017) and Wu et al (2018).…”

Section: Referring Tomentioning

confidence: 99%

“…Therefore, the above experimental database should be complemented with additional finite element simulations. Few prior studies have been conducted in this direction (Elkady andLignos 2012, 2015a;Stoakes and Fahnestock 2016;Fogarty et al 2017). However, several issues that influence the steel column stability under seismic loading have not been fully addressed.…”

Section: Introductionmentioning

confidence: 99%

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Improved Seismic Design and Nonlinear Modeling Recommendations for Wide-Flange Steel Columns

Elkady

Lignos

2018

J. Struct. Eng.

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This paper presents the findings of parametric finite element (FE) simulations of more than 50 wide-flange steel columns under cyclic loading. The column sizes, which are mostly highly ductile according to the current design practice in North America, are those seen in new and existing steel seismic-resistant moment frames. The parametric study is based on a high-fidelity FE model, which is thoroughly validated with available full-scale steel column experimental data. In the FE simulations, variations in the employed lateral loading history, the applied axial load ratio were considered to assess and refine a number of provisions related to the seismic design of steel MRF columns. The assessment is based on a number of performance indicators including the column axial shortening and corresponding plastic hinge length, the column plastic rotation capacity influenced by local and global geometric instabilities, as well as the lateral stability bracing force demands. Empirical expressions are proposed to estimate these performance indicators as a function of geometric and loading parameters. Based on these expressions, seismic design recommendations are proposed to maintain column stability. A comparison with the current ASCE 41-13 nonlinear modeling provisions for steel columns is also made and specific recommendations are proposed to update the limits for force-controlled wide-flange steel columns.

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Section: Referring Tomentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Improved Seismic Design and Nonlinear Modeling Recommendations for Wide-Flange Steel Columns

Elkady

Lignos

2018

J. Struct. Eng.

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“…Furthermore, steel MRF columns often carry substantial axial force and are in the vertical load path, such that their potential loss of axial load carrying capacity has severe implications for global collapse. As a result, the cyclic inelastic response of columns, with an emphasis on their cross-sectional and lateral-torsional stability and the ensuing loss of lateral and vertical load carrying capacity has recently gained attention in research (Elkady and Lignos 2018a;b;Fogarty et al 2017;Fogarty and El-Tawil 2016;Ozkula et al 2017;Lignos 2015, 2018a;Wu et al 2018). This research has yielded new information regarding the influence of various parameters (e.g., cross-sectional properties including width-thickness ratios, load histories, and boundary conditions) on the column's hysteretic response, deformation capacity, and lateral-torsional stability.…”

Section: Introductionmentioning

confidence: 99%

“…shows the definition of column axial shortening, δaxial,β considering the degree of column base flexibility, δv,β with reference to the undeformed, and pinned column case δv,pin. Physical column testing(Elkady and Lignos 2018a;MacRae et al 1990;Ozkula et al 2017;Suzuki and Lignos 2015) complemented by CFE simulations Lignos 2015a, 2018b;Fogarty et al 2017;Fogarty and El-Tawil 2016) suggest that column axial shortening is a primary failure mode currently not addressed in seismic code provisions; thus recent recommendations focus on how to limit column axial shortening in the context of seismic design provisions of steel MRFs(Elkady and Lignos 2018b;Wu et al 2018), typically resulting in a heavier column design depending on the applied compressive axial load ratio. Recent work(Cravero et al 2018; Lignos 2015, 2018a) suggests that column axial shortening may control decisions associated with reparability in the aftermath of earthquakes.…”

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confidence: 99%

Seismic Stability of Wide-Flange Steel Columns Interacting with Embedded Column Base Connections

2019

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The rotational flexibility of column base connections is commonly assumed to be detrimental to the seismic response of steel Moment Resisting Frames (MRFs) because it increases story drift demands and promotes soft-story formation by lowering the point of inflection, thereby exacerbating the moment demand at the first-story column top end. However, recent experimental research indicates that wide-flange steel columns with flexible boundary conditions may show enhanced response because base connection flexibility delays the plastic hinge formation and local buckling progression within the column cross-section near the base. Local buckling greatly reduces the lateral and torsional restraint at the column ends such that the delay in local buckling also delays member instabilities, which often control the deformation capacity of wide-flange steel columns. This effect is examined parametrically through 2160 Continuum Finite Element (CFE) simulations validated against physical experiments. Parameters interrogated include the applied axial load ratio, the column length, and the lateral loading protocol for the column sections, along with five levels of column base connection flexibility. The results indicate that base connection flexibility has a significant (and positive) influence on key aspects of column response, including: (1) lateral deformation capacity, which is on average 40~50% greater for a realistic value of flexibility, relative to a fixed-base condition, and (2) residual column axial shortening, which is important from the standpoint of retrofit and reparability (a 30-60% decrease). These benefits are more pronounced in cyclic (versus monotonic) loading histories and for members with cross-sections more prone to out-of-plane instability.

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“…Ruiz-García et al [16] studied the response of three-dimensional steel moment-resisting buildings having three-, nine-, and twenty-story heights under the bidirectional attack of real seismic sequences with different earthquake ground-motion features. Many other important studies aimed at meeting specific objectives, but following the general goal of evaluating the seismic behavior of steel frames with medium columns, can be found in the literature [17][18][19][20][21].…”

Section: Introduction and Literature Reviewmentioning

confidence: 99%

Comparison between the Dynamic Responses of Steel Buildings with Medium and Deep Columns under Several Seismic Intensities

Valenzuela-Beltrán,

Llanes-Tizoc,

Bojorquez

et al. 2024

Applied Sciences

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Structural engineers often use deep columns in high seismic areas to reduce drifts, yet this somehow contradicts what is stated in some tests in the sense that even though deep columns may satisfy current seismic provisions, they can suffer premature twisting; this is an indication that a lot of research is needed in this area. Numerical and experimental studies have been conducted to estimate the response of steel buildings with medium and deep columns under the action of static and cyclic loading; however, studies accounting for the dynamic characteristics of buildings and strong motions are not common. In addition, responses in terms of local parameters have not been considered either. In this study, the nonlinear seismic responses of steel buildings with perimeter moment-resisting frames and medium (W14) columns are numerically calculated and compared to those of similar steel buildings with equivalent deep columns in terms of cost (W27 and larger). Low-, mid-, and high-rise steel building models with different dynamic characteristics, as well as several strong motions with different frequency contents, are considered. Results indicate that the drifts of the models with medium columns may be up to 140% greater than those of the models with deep columns. Significant reductions are also observed for top displacements, normalized interstory shears, and combined normalized axial loads and bending moments. Hence, the seismic demands of the buildings with deep columns may be much smaller than those of the buildings with medium columns and, therefore, the buildings with deep columns exhibit a superior behavior, which results in more economical designs. The reduction is greater for the case of low- and mid-rise buildings than for high-rise buildings. One of the reasons for this is that as medium columns are replaced by deep columns, the stiffness and the strength increase, which are lower in the tallest model.

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Collapse Response and Design of Deep Steel Columns Subjected to Lateral Displacement

Cited by 20 publications

References 6 publications

Improved Seismic Design and Nonlinear Modeling Recommendations for Wide-Flange Steel Columns

Improved Seismic Design and Nonlinear Modeling Recommendations for Wide-Flange Steel Columns

Seismic Stability of Wide-Flange Steel Columns Interacting with Embedded Column Base Connections

Comparison between the Dynamic Responses of Steel Buildings with Medium and Deep Columns under Several Seismic Intensities

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