Joint panel in steel moment connections, Part 1: Experimental tests results

Rahiminia, Faramarz; Namba, Hisashi

doi:10.1016/j.jcsr.2013.07.002

Cited by 17 publications

(5 citation statements)

References 8 publications

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“…Figure b presents the fractured beam end in the connection zone . Usually, the local fracture does not change the overall dynamic features of the steel frame, which brought significant challenges to traditional system identification techniques.…”

Section: Numerical Examplesmentioning

confidence: 99%

“…Figure 4b presents the fractured beam end in the connection zone. 23 Usually, the local fracture does not change the overall dynamic features of the steel frame, which brought significant challenges to traditional system identification techniques. The second case study provided the local damage identification of the beam end, regardless of the slight change of the overall dynamic features.…”

Section: Numerical Examplesmentioning

confidence: 99%

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Physical‐based parametrization and local damage identification for frame‐type structures using response sensitivity approach in time domain

Guo

Deng

Wang

et al. 2019

Struct Control Health Monit

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Summary Structures are usually subjected to some specific local damages or weaknesses, which cannot be explained by uniformly distributed stiffness or mass changes, especially when the local damages or weaknesses have slight influences on global natural periods or vibration modes. Furthermore, large amounts of measurement positions are in need to capture the damage location and severity in traditional damage identification, and results easily depend on the initial estimates of the unknown parameters for the iterative update. To circumvent the above problems, a novel framework is proposed, involving strategies for physical‐based parametrization and local damage identification for frame‐type structures. The novelty of this research lies in the careful integration of the physical‐based parameterization and the identification techniques to robustly quantify commonly encountered local damages, namely, the weakness in exposed column base and partially fractured beam end. In this framework, the guidance for the application of physical‐based parametrization is provided, and thus, the above‐mentioned local damages of structures could be parametrized in an appropriate and convenient way. The response sensitivity approach is employed to derive the parameters by directly using time domain data. Derivatives of the stiffness matrix with respective to the newly introduced physical parameters are directly proposed so that no finite difference method is involved. Furthermore, trust‐region restriction is adopted to enhance the efficiency and stability of the identification approach when facing strong convergence difficulty or way‐out initial estimates. Two case studies are presented to validate the effectiveness and accuracy of the proposed framework. The shell element‐based models with intentional damage and weakness are built in ABAQUS to provide the data source. Two corresponding beam element‐based models are developed in MATLAB as physical‐based parametrized models. Results show that damages are accurately and efficiently estimated by the proposed framework, and the original dynamic responses are well reproduced by the identified models. Comparisons to the results by Bayesian estimation are also discussed.

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Section: Numerical Examplesmentioning

confidence: 99%

Section: Numerical Examplesmentioning

confidence: 99%

Physical‐based parametrization and local damage identification for frame‐type structures using response sensitivity approach in time domain

Guo

Deng

Wang

et al. 2019

Struct Control Health Monit

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“…The panel zone displacement was computed from the measured displacements by the LVDTs Nos. 4 and 5 by following the procedure discussed in the works of Fielding and Huang[23] and Rahiminia and Namba[24]. The results in the figure indicate that the maximum panel zone displacements…”

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confidence: 95%

Structural Performance of a New Blind-Bolted Frame Modular Beam-Column Connection under Lateral Loading

et al. 2019

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This study proposes an effective steel frame modular system and evaluates the structural performance of its beam-column connection through experimental and analytical work. The new steel frame modular system utilizes the blind bolts, which allow free access to the structural members of the closed cross-section. In addition, the new modular system is designed such that the strength of its beam members is considerably lower than that of its column members to implement the strong column-weak beam concept. In order to investigate the effectiveness of the proposed modular beam-column connection, two types of specimens were designed and tested. One of the two specimens has four knee brace members to increase the bending stiffness of the connection, while the other does not have these components. The applied load versus displacement curves are plotted for the two specimens, and their failure modes are identified. Finally, a simplified analytical model for the modular beam-column connection is proposed, and its effectiveness is validated by performing its push-over analysis and comparing its results with the test results.

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“…Recent test findings 9–14 suggest that prequalified welded unreinforced flange‐welded web (WUF‐W) connections with highly inelastic panel zones (i.e., shear distortions up to

25{\gamma _y}

) are not susceptible to fractures at the beam flange‐to‐column flange region even at lateral drift demands of 4% rads. This is attributed to today's improvements in weld specifications and fabrication practices 12,15–17 .…”

Section: Introductionmentioning

confidence: 99%

“…However, following the 1994 Northridge and 1995 Kobe earthquakes, it was found that steel MRF connections that featured inadequate base and weld material toughness requirements had a high fracture potential when their panel zones exhibited inelastic shear distortions higher than 4𝛾 𝑦 7,8 (where 𝛾 𝑦 is the panel zone shear distortion at yield). Recent test findings [9][10][11][12][13][14] suggest that prequalified welded unreinforced flange-welded web (WUF-W) connections with highly inelastic panel zones (i.e., shear distortions up to 25𝛾 𝑦 ) are not susceptible to fractures at the beam flange-to-column flange region even at lateral drift demands of 4% rads. This is attributed to today's improvements in weld specifications and fabrication practices.…”

Section: Introductionmentioning

confidence: 99%

Seismic demands of steel moment resisting frames with inelastic beam‐to‐column web panel zones

Skiadopoulos

Lignos

2022

Earthq Engng Struct Dyn

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This paper intends to provide quantitative seismic response characteristics of steel moment resisting frames (MRFs) with inelastic beam‐to‐column panel zone joints. Two modeling approaches are proposed for this purpose along with a methodology to consider the fracture potential at the bottom beam flange in steel MRFs due to panel zone kinking. Both approaches, which are validated with available experiments, preserve the behavioral insights of inelastic panel zones. Nonlinear static and dynamic analyses are then conducted to quantify the seismic demands of 32 prototype steel MRFs while their panel zones exhibit various levels of inelastic deformations. Engineering demand parameter hazard curves are developed to interpret the results for a risk‐targeted seismic performance. The results demonstrate that steel MRFs with panel zone shear distortions of 10 to 15 times the shear distortion at yield, γy${\gamma _y}$, have a mean annual frequency of collapse ranging from 1.5×10−4$1.5 \times {10^{ - 4}}$ to 2.5×10−4$2.5 \times {10^{ - 4}}$, which is up to two times lower than corresponding results with code‐compliant steel MRFs (i.e., γ≤4γy).$\gamma \le 4{\gamma _y}).$ It is shown that steel MRFs with inelastic deformations of 10γy${\gamma _y}$ in their panel zones, (a) enjoy up to 50% reduction in residual story drift ratios at a design basis earthquake; (b) their beam‐to‐column connections do not experience fractures due to panel zone kinking; and (c) local buckling in steel beams is very limited even at low probability of occurrence earthquakes. The above hold true when the current detailing and fabrication practice is employed. The findings have implications on seismic design and the post‐seismic repairability of steel MRFs.

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Joint panel in steel moment connections, Part 1: Experimental tests results

Cited by 17 publications

References 8 publications

Physical‐based parametrization and local damage identification for frame‐type structures using response sensitivity approach in time domain

Physical‐based parametrization and local damage identification for frame‐type structures using response sensitivity approach in time domain

Structural Performance of a New Blind-Bolted Frame Modular Beam-Column Connection under Lateral Loading

Seismic demands of steel moment resisting frames with inelastic beam‐to‐column web panel zones

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