자료유형  

 학위논문

Control Number  

0017161690

International Standard Book Number  

9798382809939

Dewey Decimal Classification Number  

620

Main Entry-Personal Name  

Masungi, Parfait Mangwaka.

Publication, Distribution, etc. (Imprint  

[S.l.] : Princeton University., 2024

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2024

Physical Description  

297 p.

General Note  

Source: Dissertations Abstracts International, Volume: 85-12, Section: B.

General Note  

Advisor: Garlock, Maria Eugenia Moreyra.

Dissertation Note  

Thesis (Ph.D.)--Princeton University, 2024.

Summary, Etc.  

요약Thin steel plates can resist large shear forces in rolled beams, built-up deep beams (plate girders), and shear walls. When designing large-scale structures, structural engineers can efficiently maximize the shear and flexural resistance of steel plate girders by increasing the depth while minimizing the thickness, which consequently produces more slender webs. However, slender webs are susceptible to a failure phenomenon known as "shear buckling." The objective of this dissertation was to discover and quantify the relationship between out-of-plane patterns on webs of plate girders and the structural strength of plate girders via two specific studies: (1) web out-of-flatness imperfections developed during fabrication, and (2) a type of corrugation in the web plate called "low-frequency sinusoids" (LFS) were examined for both the shear and flexural strength of plate girders. Field measurements, experimental tests, and finite element analyses were the methods employed to meet this objective.During the fabrication stage of welded built-up sections designed with deep webs, not all flat webs remain perfectly straight due to the inevitable effects of rolling, forming, welding, handling, and assembling. The fabrication-induced out-of-flatness patterns on webs are random in size and shape and will impact the shear strength. Various design code specifications in the U.S. and worldwide have provided tolerance limits for fabrication imperfections without any engineering or scientific basis. This dissertation provides qualitative and quantitative data to demonstrate the effects of out-of-flatness imperfections on the shear strength of thin steel webs.The findings of this pioneering research reveal the following:(1) The field measured (as-fabricated) out-of-flatness imperfections do not follow the patterns of the first or second numerical eigenmode and possess larger shear capacity than similar webs examined with eigenmode imperfections. This conclusion is important since all numerical studies to-date use eigenmodes as the initial imperfection, thus leading to appropriately conservative results.(2) Regardless of the initial shape and magnitude of web imperfections, shear buckling in thin webs is a plastic yield mechanism failure penetrating through the web thickness in three stages: elastic stage 1, web mechanism stage 2, and panel mechanism stage 3.(3) The fabrication procedure of LFS plate girders using the roll forming and bump and press forming techniques will increase the shear strength of plate girders by a maximum of 46% above that of flat webs.(4) The elastic lateral-torsional buckling (LTB) strength of LFS plate girders with slender webs as compared to flat webs can increase by up to 9%.Overall, this research leads to important conclusions on the effects of initial imperfections and appropriate methods of their consideration in numerical and experimental studies. The research also enables the development of appropriate fabrication and design specifications for constructing large-scale structures.

Subject Added Entry-Topical Term  

Engineering.

Subject Added Entry-Topical Term  

Materials science.

Index Term-Uncontrolled  

Imperfections

Index Term-Uncontrolled  

Low-frequency sinusoids

Index Term-Uncontrolled  

Shear buckling

Index Term-Uncontrolled  

Shear mechanism

Index Term-Uncontrolled  

Steel web plates

Index Term-Uncontrolled  

Tolerance limits

Added Entry-Corporate Name  

Princeton University Civil and Environmental Engineering

Host Item Entry  

Dissertations Abstracts International. 85-12B.

Electronic Location and Access  

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Control Number  

joongbu:655083