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Last fall, Manitoba's most well-known landmark was returned to its place atop the Manitoba legislative building. The Golden Boy was not only restored - it was also equipped with sensors, including fibre-optic sensors, that detect structural problems before they become critical.
Researchers now know immediately when the Golden Boy is in poor health.
In 2002, the 85-year-old structure was removed from the dome of the Manitoba
legislature after engineers discovered severe corrosion in the 5" diameter
steel support column which extends inside the statue from heel to chest.
When the statue was returned to its perch in September, it had received
more than a re-gilding and a new steel support column. It had become the
country's first cultural icon to use fibre-optic monitoring.
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Standing tall and proud
ISIS Canada has embarked on a new research project to aid in safeguarding Canada's 350,000 veterans' grave markers from structural damage. The $85,000 project, with Veteran Affairs Canada and Public Works and Government Services Canada, is studying the feasibility of replacing steel reinforcements with fibre-reinforced polymers in the concrete beams and the grave marker connections to those beams. Fibre-reinforced polymers do not corrode like steel reinforcements. In a separate field trial, ISIS researchers will use fibre-optic sensors to monitor the structural health of these innovative structural systems in Brookside Cemetery in Winnipeg.
"At Brookside, there's quite a problem with soil settlement and the concrete beams, which are causing some of the markers to sink or tilt," says Doug Stephenson, a senior engineer with the Heritage Conservation Services unit of Public Works and Government Services Canada.
"The problems aren't unique to Winnipeg or this particular cemetery," he adds. "We would be looking at the potential of applying this solution to other cemeteries across Canada." ISIS Canada will prepare a report on its findings next spring.
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Spearheaded by Dr. Aftab Mufti at ISIS Canada and with financial support from the Manitoba government, the monitoring project is designed to detect potential problems before they become critical. Instruments installed inside the statue on the support column measure the effects of wind, precipitation and temperature, particularly in the heel - the weakest point of the 1,650-kg statue.
"If the Golden Boy didn't have sensors, maintenance crews would have to periodically climb the dome to do visual inspections, or take the statue down for detailed assessment," says Dr. Mufti, president of ISIS Canada and a professor of civil engineering at the University of Manitoba. "Using this technology, decisions on whether to replace a structure can be based on real data. It will also better equip us for predicting how long a structure will last, and when it will require maintenance."
Two accelerometers at the top of the support column measure the vibration of the Golden Boy, and a combination of strain gauges and fibre-optic sensors at the column base measure wind stress effects. Temperature gauges help monitor climate effects on the support column. Wires for the sensor system run down into the building dome and connect to a monitoring unit inside the building. Data from the unit are updated every five seconds and can be viewed online at: http://130.179.57.204/ActiveSHM/
GBmainpages/GBhome.htm.
The health monitoring system uses fibre Bragg grating (FBG) optical sensors developed by ISIS Canada. This same technology is used in about 40 structures in Canada, including the Confederation Bridge connecting Prince Edward Island to the mainland. ISIS is also monitoring the Portage Creek Bridge in Victoria, B.C. to measure the effect earthquakes have on the structure. In another ISIS project, researchers from the University of Toronto and University of Alberta are using FBG sensors to conduct remote monitoring of pipelines. This same technology can also be used in airplanes, buildings, ships and even nuclear reactors.
"Canada is well known internationally as a leader in this area," says Dr. Mufti, who worked closely with Dillon Consulting of Winnipeg on the project. "Because of organizations like ISIS, Canada was an early adopter of fibre Bragg gratings. Not only does ISIS promote the use of new materials, it also makes it possible for experts in this field from across Canada to work together."
ISIS is promoting the technology to contractors and engineering consultants, who Dr. Mufti says are "becoming very interested. By knowing what is going on inside of structures," he adds, "we can better predict how long structures will last and when maintenance will be required."
www.isiscanada.com
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