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Seismic Collapse Hazard of Steel Braced Framed Buildings and Innovative C-TnT Braces for Retrofitting.

紀錄類型:	書目-語言資料,手稿 : Monograph/item
正題名/作者:	Seismic Collapse Hazard of Steel Braced Framed Buildings and Innovative C-TnT Braces for Retrofitting./
作者:	Zhang, Hanming.
面頁冊數:	1 online resource (128 pages)
附註:	Source: Dissertations Abstracts International, Volume: 85-03, Section: B.
Contained By:	Dissertations Abstracts International85-03B.
標題:	Environmental engineering. -
電子資源:	click for full text (PQDT)
ISBN:	9798380155649

Seismic Collapse Hazard of Steel Braced Framed Buildings and Innovative C-TnT Braces for Retrofitting.
Zhang, Hanming.

Seismic Collapse Hazard of Steel Braced Framed Buildings and Innovative C-TnT Braces for Retrofitting. - 1 online resource (128 pages)

Source: Dissertations Abstracts International, Volume: 85-03, Section: B.

Thesis (Ph.D.)--Iowa State University, 2023.

Includes bibliographical references

Concentrically braced frames (CBFs) are one of the most commonly used lateral force resisting systems in structural engineering design, and the seismic performance of the bracing members is critical to the stability of the entire building during the earthquakes. In this dissertation, analytical studies through numerical modeling were conducted to evaluate the seismic performance of CBFs with different beam design strengths, or plan configurations, and the efficiency of using C-TnT braces to reduce the seismic collapse hazard on existing CBF buildings.From the first study of this dissertation, it was observed that the increase in beam design strengths could only delay the first fracture of bracing members, thus the improvement of seismic performance is very limited. However, if the innovative C-TnT braces were applied, even if the beams were designed considering gravity loads only, no yielding at the brace-beam intersection could be observed, thus the seismic performance could be significantly improved. The second study of this dissertation found that the simplified 2D model had shown different responses with 3D model, torsional effects brought from unsymmetrical brace inelastic behavior or fracture could amplify the risk of building collapse. The modeling results in the third study suggested that when subject to similar ground motions similar to 1994 Northridge earthquake, existing CBF buildings constructed before 1990 tend to show underestimated seismic collapse hazard due to less brace ductility failure from b/t ratios higher than 14. The fourth study of this dissertation was a continuation of the study on existing CBF buildings. By applying C-TnT braces as retrofitting scheme, it was found that the seismic collapse hazard of such existing CBF buildings was significantly reduced, and the ductility demand from modeling results was able to be satisfied by the capacity from laboratory testing results of TnT brace specimens. Findings of this dissertation have demonstrated that the research methods of using 2D modeling for seismic performance evaluation on CBF buildings could lead to underestimated collapse hazard, meanwhile the existing CBF buildings designed with old specifications could be in need of retrofitting, and using C-TnT braces as retrofitting scheme can be efficient in seismic collapse hazard reduction and cost effective comparing with other types of retrofitting schemes.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2024

Mode of access: World Wide Web

ISBN: 9798380155649Subjects--Topical Terms:

557376
Environmental engineering.
Subjects--Index Terms:

Brace fractureIndex Terms--Genre/Form:

554714
Electronic books.

Seismic Collapse Hazard of Steel Braced Framed Buildings and Innovative C-TnT Braces for Retrofitting.
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520 $a Concentrically braced frames (CBFs) are one of the most commonly used lateral force resisting systems in structural engineering design, and the seismic performance of the bracing members is critical to the stability of the entire building during the earthquakes. In this dissertation, analytical studies through numerical modeling were conducted to evaluate the seismic performance of CBFs with different beam design strengths, or plan configurations, and the efficiency of using C-TnT braces to reduce the seismic collapse hazard on existing CBF buildings.From the first study of this dissertation, it was observed that the increase in beam design strengths could only delay the first fracture of bracing members, thus the improvement of seismic performance is very limited. However, if the innovative C-TnT braces were applied, even if the beams were designed considering gravity loads only, no yielding at the brace-beam intersection could be observed, thus the seismic performance could be significantly improved. The second study of this dissertation found that the simplified 2D model had shown different responses with 3D model, torsional effects brought from unsymmetrical brace inelastic behavior or fracture could amplify the risk of building collapse. The modeling results in the third study suggested that when subject to similar ground motions similar to 1994 Northridge earthquake, existing CBF buildings constructed before 1990 tend to show underestimated seismic collapse hazard due to less brace ductility failure from b/t ratios higher than 14. The fourth study of this dissertation was a continuation of the study on existing CBF buildings. By applying C-TnT braces as retrofitting scheme, it was found that the seismic collapse hazard of such existing CBF buildings was significantly reduced, and the ductility demand from modeling results was able to be satisfied by the capacity from laboratory testing results of TnT brace specimens. Findings of this dissertation have demonstrated that the research methods of using 2D modeling for seismic performance evaluation on CBF buildings could lead to underestimated collapse hazard, meanwhile the existing CBF buildings designed with old specifications could be in need of retrofitting, and using C-TnT braces as retrofitting scheme can be efficient in seismic collapse hazard reduction and cost effective comparing with other types of retrofitting schemes.
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