DIT PhD Project
Supervisor name & contact details:
Dr. Niall Holmes
Department of Civil & Structural Engineering,
School of Civil Engineering, DIT Bolton Street
Email niall.holmes@dit.ie
Supervisors Profile:
http://dit.ie/civilandbuildingservicesengineerin
g/cbseii/research/
Research Centre (if applicable):
Research Centre website (if applicable):
Supervisors Publication List:
http://arrow.dit.ie/do/search/?q=author_lnam
e%3A%22Holmes%22%20AND%20author_fna
me%3A%22Niall%22&start=0&context=490738
&sort=date_desc
Title of the Project:
Numerical modelling of active confinement on concrete columns
This project will develop finite element models of active confinement surrounding concrete
columns.
Rehabilitation of existing reinforced concrete columns may be required for a number of reasons,
such as strengthening due to changes in occupancy or the need to improve the performance of a
structure during an earthquake. In the case of the latter, the low probability of a major seismic
event and the potentially high cost of structural upgrades make rehabilitation of the complete
structure difficult to justify economically. Therefore, the most practical solutions are often those
which lessen the risk of structural collapse through the rehabilitation of selected critical
members. In cases of reinforced columns, structural schemes designed to improve the strength
and ductility of plastic hinge regions can significantly improve performance during an earthquake.
Significant advances in the understanding of structural behaviour and the geologic science of
earthquakes have occurred over the past 40 years. Design codes before the 1970’s relied mainly
on the provision of strength to resist seismic loads without giving consideration to proper
detailing to enhance ductility and energy dissipation at potential plastic hinge locations. The lack
of strict design criteria in older reinforced concrete structures has made them particularly
susceptible to failure under seismic loading conditions. A common column detailing deficiency
found in older reinforced concrete structures is that of widely spaced transverse ties giving poor
confinement and support to longitudinal reinforcement. Confinement is required to delay the
strength degradation of concrete under ultimate load conditions and allow a ductile response of
the column. Failure of a primary member, and particularly a column, can be catastrophic leading
to a partial or complete structural collapse. As a result, many older buildings in new and existing
seismic regions require rehabilitation.
Providing confinement to columns through externally applied transverse reinforcement
configurations such as jackets, collars, straps or wraps has been identified by researchers as a
suitable rehabilitation method for under designed concrete columns. A particularly innovative
avenue of research is that of confinement methods which engage the use of active confining
forces. Where passive confinement methods rely on the dilating concrete material due to load
application to initiate the generation of confining pressures, active confinement methods apply
an initial confining pressure through pre-stressing of confinement materials resulting in
confinement being effective prior to loading.
This project will examine the influences of active confining pressures on the overall behaviour of
confined concrete and will include experimental and numerical studies.
Ciência sem Fronteiras / Science Without Borders Priority Area:
Engineering and other technological areas
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