Effect of weld details on the ductility of steel column baseplate connections

Myers, Andrew C.; Kanvinde, Amit; Deierlein, Gregory G.; Fell, Benjamin

doi:10.1016/j.jcsr.2008.08.004

Cited by 54 publications

(21 citation statements)

References 7 publications

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“…In all of the three models, this shift of cracking location is achieved by increasing the Table 1, that the parameter which is a measure of ductile fracture toughness is higher for weld than for column HAZ. These observations validate the statement made by Myers et al (2009a), which suggested that combination of the extra strength provided by RFWs and weld toughness prevented cracking in the weld root in their tests.…”

Section: Discussion On the Results Of The Studysupporting

confidence: 89%

“…The results of several research projects (Ballio et al, 1997;Barsom and Pellegrino, 2002;Stojadinovic, 2003;Myers et al, 2009a;Iyama and Ricles, 2009;Nastar et al, 2010) have revealed that ductile crack initiation and growth is a prevailing mode of failure in welded beam-tocolumn and base plate connections which prevents these connections from reaching high levels of ductility. Cracks can cause a low cycle fatigue failure; and also the damage accumulated during the next major seismic excitation or aftershock can cause the existing cracks to grow and lead to a fracture in the connection (Iyama and Ricles, 2009).…”

Section: Introductionmentioning

confidence: 99%

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Reinforcing fillet welds preventing cracks in partial joint penetration welds

Ajaei

Ghassemieh

2015

Int J Steel Struct

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In this paper, effectiveness of reinforcing fillet welds in preventing cracking in roots of partial joint penetration welds is investigated. The method used for this investigation includes finite element modeling and a micromechanical model of crack initiation. Base plate connections of three wide flange sections with various fillet weld dimensions are modeled. A novel method is proposed for idealization of the partial penetration weld geometry. The accuracy of the finite element model and the cracking initiation prediction method are verified based on test results. It is observed that, for each column section, utilizing fillet welds larger than a certain size shifts the crack initiation location from the partial penetration weld root to the column flange, which delays cracking considerably. The aforementioned minimum size of the reinforcing fillet welds depends mainly on thickness of the column flange, and also on the depth of the cross section.

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Section: Discussion On the Results Of The Studysupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Reinforcing fillet welds preventing cracks in partial joint penetration welds

Ajaei

Ghassemieh

2015

Int J Steel Struct

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“…Depending on the weld metal toughness, however, it is possible for premature fracture of the column base welds to occur. This was confirmed in experimental studies conducted by Fahmy et al (2000) and Myers et al (2009). In these studies, specimens with toughness-rated weld metal sustained about twice the drift ratios prior to fracture compared to specimens with non-toughness rated weld metal (5% versus 2.5%, respectively).…”

Section: A41 Exposed Base Platessupporting

confidence: 66%

Research plan for the study of seismic behavior and design of deep, slender wide flange structural steel beam-column members

Venture¹

2011

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The objective of this task was to develop a comprehensive long-range plan to research the seismic behavior of deep, slender wide flange structural steel beamcolumns in steel frames. Development of the plan included the investigation of available information on beam-column member and connection behavior in the literature, and considered the differences and interrelationships between member, subassemblage, and system performance. The resulting plan includes a summary of tasks for conducting both experimental and analytical research, and is intended to be the first step in the development of national consensus guidelines for designing and assessing the seismic performance of deep, slender wide-flange beam-columns in steel frame systems.The NEHRP Consultants Joint Venture is indebted to the leadership of Jim Malley, Project Director, and to the members of the Project Technical Committee, consisting of Charlie Carter, Jerry Hajjar, Dimitrios Lignos, Charles Roeder, and Mark Saunders for their contributions in developing this report and the resulting recommendations. The NEHRP Consultants Joint Venture also gratefully acknowledges Jack Hayes (NEHRP Director), Steve McCabe (NEHRP Deputy Director), Jay Harris (NIST Project Manager), Mike Mahoney (FEMA), and Helmut Krawinkler (FEMA Technical Monitor) for their input and guidance in the preparation of this report, Ayse Hortacsu for ATC project management, and Peter N. Mork for ATC report production services. Jon A. Heintz Program ManagerGCR 11-917-13 List of Tables Executive SummaryCurrent practice in modern steel frame design frequently concentrates seismic resistance into a few frames or a few bays within planar frames. In moment resisting frames, this practice results in column designs that are dominated by a combination of axial force and bending due to lateral deformation, rather than just axial force alone. Due to their increased in-plane flexural stiffness, deeper column sections are generally selected to satisfy drift criteria and to balance relative stiffness with deep beam sections. Columns that are generally stocky, in terms of both member stability and cross-sectional compactness requirements, are expected to perform well under seismic loading. Deeper, more slender columns, however, are more vulnerable to weak-axis and local buckling failure modes, and these sections must be checked against the potential for in-plane and out-of-plane instability under combined axial load and bending moment.The term deep refers to member depths that are nominally greater than 16 inches (i.e., W16 sections and larger). The term slender refers to members that are sensitive to instability or have cross-sectional elements with width-to-thickness ratios approaching the seismic compactness limits for highly ductile members. An area of critical need identified by the American Institute of Steel Construction (AISC) is the seismic performance of deep, slender, wide flange structural steel beam-column members when subjected to a range of axial loads. Research on the stability of th...

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“…Eqs. (2) and (3) represent the kinematic translation of the yield surface, based on two backstress tensors (i.e., α 1 and α 2 ). Each backstress tensor represents a component of the center of the yield surface (and thus its translation).…”

Section: Constitutive Modelmentioning

confidence: 99%

“…Sophisticated FE simulations have recently been used to characterize the response of structural steel braces, connections as well as steel plate shear walls [1][2][3]. More specifically, the various objectives of these simulations include modeling the load-deformation response of structures and components (e.g., [4]), characterizing internal stress and strain distributions, and predicting failure modes such as fracture, based on these internal distributions (e.g., [5]).…”

Section: Introductionmentioning

confidence: 99%

Constitutive parameter calibration for structural steel: Non-uniqueness and loss of accuracy

Cooke¹,

Kanvinde

2015

Journal of Constructional Steel Research

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a b s t r a c tFinite element (FE) simulations used to characterize extreme limit states in steel structures require the calibration of numerous parameters. Calibration of these models for large strains (greater than 0.3 or so) cannot be performed using stress-strain curves on standard tests, since the stress state in these tests becomes non-homogenous due to necking or buckling which occur at lower strains. As a result, calibration is often performed by matching load-displacement curves of calibration specimens to those obtained through complementary FE simulations. In these situations, multiple parameter sets produce strain fields that match the measured load-displacement response, resulting in non-unique parameter fits. A series of 2400 FE simulations with 4 specimen geometries, 300 material parameters sets, and 2 loading histories indicates that multiple trial parameter sets produce excellent load-displacement match with the true material response, implying that the method is highly susceptible to nonunique fitting. All simulations use the Armstrong and Frederick constitutive model with a von Mises yield surface. The impact of non-unique fitting is assessed through FE simulations based on parameter sets that show excellent load-displacement match with calibration specimens. It is determined that the non-uniqueness does not significantly affect the prediction of peak force. However, it severely impacts the accuracy in prediction of internal plastic strains, with errors as large as 50% with respect to the true material. This has serious implications for FE simulation used to characterize extreme, strain-based limit states such as fracture. Strategies for mitigation of this inaccuracy are presented, along with limitations of the study.

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Effect of weld details on the ductility of steel column baseplate connections

Cited by 54 publications

References 7 publications

Reinforcing fillet welds preventing cracks in partial joint penetration welds

Reinforcing fillet welds preventing cracks in partial joint penetration welds

Research plan for the study of seismic behavior and design of deep, slender wide flange structural steel beam-column members

Constitutive parameter calibration for structural steel: Non-uniqueness and loss of accuracy

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