This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.
Permalink
https://hdl.handle.net/2142/23216
Description
Title
Connections to concrete-filled steel tubes
Author(s)
Alostaz, Y.M.
Issue Date
1996
Doctoral Committee Chair(s)
Schneider, Stephen P.
Department of Study
Civil and Environmental Engineering
Discipline
Civil and Environmental Engineering
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Engineering, Civil
Language
eng
Abstract
The objective of this research program was to study connections to concrete-filled steel tubes. This research focused on the connection to circular steel tubes, because this shape presents more detailing difficulties compared to the square counterpart. To accomplish the goals of this study, the research was divided into three phases: prototype frame design and analysis, a finite element analysis of several connections, and an experimental study on six large-scale connection specimens. In the first phase, two prototype moment-resisting steel frames were designed to satisfy the 1991 NEHRP Provisions. The inelastic performance of these frames was studied, and the connections with the highest ductility demand were isolated. The second phase of the research was devoted to the inelastic finite element analysis of several connection details. A 3-D finite element model was developed for each connection detail. The parameters used in the analytical study included: the diameter-to-tube wall thickness ratio, the applied axial load on the column, the moment-to-shear ratio of the girder, and the yield strength of the steel tube. In the third phase of the research, six 2/3rd-scale specimens were fabricated and tested with the quasi-static method. The flexural strength of the connection was the primary concern in this study. The analytical models and each experimental specimen were a T-shape configuration. A monotonic load was applied to the analytical finite element models. For the test specimens, a predetermined cyclic displacement was imposed at the girder tip, and the specimens were tested to destruction.
Analytical and experimental results suggest that connections which attach exclusively to the tube wall exhibit large distortion of the tube wall in the connection vicinity, thus preventing the development of the girder flexural strength. Using external diaphragms improved the simple connection behavior, however, the performance was susceptible to the geometry of the diaphragm. The behavior was significantly improved when part of the girder forces was transferred to the concrete core. However, the improvement in behavior depended on the connection detail. Continuing the girder through the concrete-filled steel tube was the most effective method to develop the full plastic hinge in the connected girder.
Use this login method if you
don't
have an
@illinois.edu
email address.
(Oops, I do have one)
IDEALS migrated to a new platform on June 23, 2022. If you created
your account prior to this date, you will have to reset your password
using the forgot-password link below.
