|
 |
|
Smart
Structures for Bridges
The Need
|
The critical
deterioration of transportation infrastructure across the
continent, including highways and bridges, has driven the
search for new methods of concrete rehabilitation and repair. There
has been a new trend in civil engineering called 'smart
structures', incorporating sensors in some of the most
advanced building materials. The researchers
would also like to install smart structures and to develop remote systems that would allow
monitoring by centrally located computers, rather than the
time and expense involved in sending work crews for on-site
inspections.
|
Confederation Bridge, Canada
|
The Technology
|
Researchers at University of
Toronto's Institute for Aerospace Studies (UTIAS) are experimenting
with a "smart" structure on the Leslie Street bridge
in northern Toronto. The project, involves lining the bridge's columns
with fiber optic sensors and wrapping them with advanced
composite materials -- light-weight synthetic that covers the
structure like plastic sandwich wrap. The wrap lessens the
deterioration and holds the structure together, while the
sensors precisely measure possible corrosion that may be
occurring underneath. All of this means less road maintenance
in general and ultimately less road closures.
The new Taylor bridge in
Headingley, Manitoba is outfitted with 66 fiber
optic sensors. The instrumentation in
the Headingley Bridge will allow Manitoba Highways and
Transportations (MHT) engineers to actively monitor the
behavior of the bridge structure and the new advanced
materials, over time. It will also allow dynamic sensing of
singular overweight events - for example, when MHT engineers
grant permission for transportation of large and overweight
loads across the bridge. They¹ll be able to see the response
of the structure in real time.
The smart structure is also
applied to Confederation Bridge, the longest bridge over
iced-water spanning 12.9 km from
Prince Edward Island to New Brunswick, Canada, to monitor the
long-term effects of wind, ice and traffic loads on the
bridge.
|
Taylor Bridge, Manitoba, Canada
Sensors from ElectroPhotonics
Corp.
The longest bridge
over iced-water spanning 12.9 km
from Prince Edward Island to New Brunswick
|
|
The
fiber optic sensors are the same kind of hair-thin cables used
in the telecommunications industry except they are wrapped
around or embedded in concrete structures. Fiber
optic sensing was a natural outgrowth of aerospace research,
because of its use in monitoring aeronautical and space
structures composed of advanced materials. The cross-over of
this advanced scientific research from aerospace to civil
engineering is exemplified by both the UTIAS Lab. and
ElectroPhotonics Corp. The
UTIAS laboratory is funded by Intelligent Sensing for
Innovative Structures (ISIS) Canada, a federal Networks of
Centres of Excellence program headquartered at the University
of Manitoba.
|
The Benefits
|
The application of
smart structure for bridges provides benefits:
- Less time and expenses in
inspections.
- The response of the
structure can be monitored remotely in
real time.
- Performance of the new advanced
composite materials can be monitored.
- The long-term performance of
advanced composite materials can be compared to conventional
girders in the bridge, also outfitted with fiber optic
sensors.
|
Status
|
ElectroPhotonics Corp. has
installed on-site one of its commercially-available Fibre
Optic Grating Strain Indicator (FOGSI) systems complete with
remote monitoring capability via phone line, for querying the
sensors and compiling their data. Research is currently
underway between ElectroPhotonics Corp. and the UTIAS FOS Lab.
to develop demodulation devices that will read and compile
data from a number of sensors simultaneously.
The Canadian Precast/Prestressed
Concrete Institute presented Precast/Prestressed
Concrete Institute’s Harry H. Edwards Award for Industry
Advancement to Wardrop Engineering Inc., as well as
participatory awards to the bridge owner, the Province of
Manitoba; the innovator of the new technology, ISIS Canada
(Intelligent Sensing for Innovative Structures); and the
pre-caster, Con-Force Structures Limited. |
Barriers
|
Fiber
optic sensors is still considered to be expensive technology
and no further data on the evaluation of its performance and
its use as feedback in decision making process for bridge
maintenance and rehabilitation processes. |
Points of Contact
- Dr. Roderick
Tennyson, Director, GRIP, Univ. of Toronto, Phone: (416)
667-7710, E-mail: rcten@utias.utoronto.ca
- Dr. T. Alavie, E-TEK
ElectroPhotonics Solutions, 7941 Jane Street, Unit 200, Concord
ON L4K 4L6 2770 14th Avenue, Markham, Ontario, Canada L3R 0J1,
Phone: (905) 946 1336, Fax: (905) 946 0190
References
- ElectroPhotonics Corporation OnLine,
http://www.electrophotonics.com/
- First Long Gauge Fibre Optic
Sensors on Leslie Street Bridge in Toronto, News Releases,
April 20, 1998, ISIS, http://www.umanitoba.ca/centres/isis/newsreleases/news5.htm
- Globe Technology,
"U of T scientists test out 'smart' bridge", April 3,
1998, http://www.globetechnology.com/archive/gam/News/19980430/UBRIDM.html
- Manitoba's 'Smart' Bridge
Communicates with Fibre Optics, News Releases, October 1997,
ISIS, http://www.umanitoba.ca/centres/isis/newsreleases/news9.htm
- Manitoba’s 'Smart' Bridge Wins
International Award for Industry Advancement, News Releases,
October 8, 1998, ISIS, http://www.umanitoba.ca/centres/isis/newsreleases/news3.htm
- Stevan de Sausa, "Smart
Concrete May Mean Less Road Closures",
Eureka Alert, http://www.eurekalert.org/releases/UT-ConRoadCl.html
Disclaimer Statement
|
Neither the Construction
Industry Institute nor Purdue University in any way endorses this
technology or represents
that the information presented can be relied upon without further investigation. |
MA26
|
