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Seismic Performance and Design of Japanese Steel Chevron-Braced Moment-Resisting Frames
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| Title: | Seismic Performance and Design of Japanese Steel Chevron-Braced Moment-Resisting Frames |
| Other Titles: | ブレース付ラーメン鋼架構の耐震性能と設計 |
| Authors: | Lopes Dias, Ilanildo Renato Browse this author |
| Issue Date: | 23-Mar-2023 |
| Publisher: | Hokkaido University |
| Abstract: | Steel braced frames are widely used for buildings in high-seismicity regions due to their versatility in meeting stiffness and strength requirements. Japanese engineers often choose to place the braces in a “chevron” (or V or inversed-V) arrangement within a moment-resisting frame (MRF). In such systems, hereafter referred to as chevron-braced MRFs, the design of the beam intersected by braces poses a design challenge because this beam yields due to forces delivered by the tension and compression braces in combination with forces produced by moment-frame action. The energy dissipating mechanism of chevron-braced MRFs is dependent on the loading history, and therefore, might not be uniquely determined becaus the structural system is statically indeterminate, and the cyclic-loading response of steel braces is highly complex. Despite the very wide use, limited design guidance is provided by the Japanese design codes and standards on how to proportion the beams and the braces and how to detail the bracin connections. The lack of guidance has allowed engineers to choose a very wide variety of designs, and this situation is at least partly responsible for the damage observed in steel chevron-braced MRFs after even the most recent earthquakes. A computational study was conducted with the following objectives: (1) to further the understanding of the seismic performance of steel chevron-braced MRFs, and thereby identify design concerns; (2) to derive proportion rules for the beams and braces in steel chevron-braced MRFs; (3) to derive bracing requirements to control the beam intersected by braces against the severe transverse forces and torsional moment delivered by the braces, and bending moments arising from moment-frame action; and (4) to assess the seismic performance of Japanese steel buildings that employ steel chevron-braced MRFs.
The computational study comprised two schemes, using 3D nonlinear finite-element-method models to examine the interaction between chevron braces and MRF, and 2D nonlinear frame models with fiber elements to examine the time-history response of building systems under strong ground motions. Both schemes utilized general-purpose software, the former a commercial package ADINA and the latter an open-source platform OpenSEES. In both schemes, basic models were validated against data and observations from an experimental study on steel chevron-braced MRFs. The validated models were used to conduct a parametric study on key design parameters such as the torsional and translational restraint of the beam intersected by braces, the relative strength of the beam with respect to the braces, and the type of bracing connection. Minimum lateral bracing requirements for the beam was recommended and design equations to estimate the torsional demands on the beam intersecting braces were proposed. Furthermore, a design procedure for chevron-braced moment-resisting frames, that accounts for the dependency of the energy dissipation mechanism on the cyclic loading history was proposed. The numerical study on the single-story single-bay chevron-braced moment-resisting frames was supplemented with an extensive number of numerical simulations to study the performance of low and mid-rise chevron-braced frames designed using different design philosophies often used in Japan.
The seismic performance of the chevron-braced-frame systems was assessed through monotonic pushover and nonlinear time history analysis. Finally, recommendations for analysis and design of chevron-braced MRFs are provided aimed at ensuring an acceptable performance of the system |
| Conffering University: | 北海道大学 |
| Degree Report Number: | 甲第15373号 |
| Degree Level: | 博士 |
| Degree Discipline: | 工学 |
| Examination Committee Members: | (主査) 教授 岡崎 太一郎, 教授 菊地 優, 准教授 高井 伸雄 |
| Degree Affiliation: | 工学院（建築都市空間デザイン専攻） |
| Type: | theses (doctoral) |
| URI: | http://hdl.handle.net/2115/89491 |
| Appears in Collections: | 学位論文 (Theses) > 博士 （工学）
課程博士 (Doctorate by way of Advanced Course) > 工学院(Graduate School of Engineering)
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