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|Title: ||Effect of corner radius on the performance of CFRP-confined square concrete columns|
|Other Titles: ||Zhuan jiao ban jing dui xian wei zeng qiang cai liao wai bao fang xing duan zhu xing neng de ying xiang|
|Authors: ||Wang, Leiming (王雷鳴)|
|Department: ||Department of Building and Construction|
|Degree: ||Master of Philosophy|
|Issue Date: ||2007|
|Publisher: ||City University of Hong Kong|
|Subjects: ||Columns, Concrete.|
Reinforced concrete construction.
|Notes: ||xvii, 181 leaves : ill. 30 cm.|
Thesis (M.Phil.)--City University of Hong Kong, 2007.
Includes bibliographical references (leaves 119-131)
CityU Call Number: TA683.5.C7 W36 2007
|Abstract: ||Jacketing confines concrete, and hence increases the strength and ductility of
jacketed columns. A significant amount of research has been devoted to circular
columns that have been retrofitted with fiber reinforced polymer (FRP), but much
less is known about FRP-confined rectangular/square columns in which the concrete
is non-uniformly confined and the effectiveness of confinement is much reduced.
Some studies suggest that a sharp corner (i.e., a zero corner radius) offers no
confinement. However, most published research indicates that a certain degree of
effective confinement is provided by a jacket with sharp corners. To further study
this problem, this study undertook compressive testing to investigate the effect of
corner radius on the strength and ductility of FRP-confined concrete columns. This
thesis reports a series of tests on 108 Carbon FRP (CFRP) confined short concrete
columns. The primary variables in the investigation were the corner radius,
transverse jacket stiffness, and concrete grade. The test results demonstrated that the
corner radius ratio is proportional to the increase in confined concrete strength.
Furthermore, it is revealed and explained that confinement provided by a jacket with
sharp corners is insignificant in increasing the strength of columns but significant in
increasing the ductility of columns.
Based on the experimental test, a strength model was developed to predict the
compressive strength of FRP-confined square columns. First, the existing models for
predicting the compressive strength of FRP-confined circular columns were assessed
by comparing them with the experimental test data collected from the open literature.
A model was then developed for circular columns based on the database. A shape
factor, which is expressed as a function of the corner radius ratio, was then suggested
to be used directly in the model proposed for circular sections to predict the confined
strength of square columns. The results predicted by this model showed a good
agreement for specimens at lower confinement levels, although they were a little
conservative at higher confinement levels. This model was proved to be suitable for
both square and circular columns.|
|Online Catalog Link: ||http://lib.cityu.edu.hk/record=b2268785|
|Appears in Collections:||BC - Master of Philosophy |
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