Winnipeg Free Press, Friday, January 10, 2003
Science & Technology Page A06

By Helen Fallding

A Headingley bridge over the Assiniboine River is beaming signals to the world and the message is a happy one.

The Taylor Bridge, billed five years ago as the smartest bridge in the world, has proven that new-age materials lighter than steel and 10 times stronger are up to the real-world challenges of truck traffic.

"It will definitely last twice the age of the steel (bridges) by our calculations, 100 years," said Aftab Mufti, president of Intelligent Sensing for Innovative Structures at the University of Manitoba.

ISIS Canada's "smart" bridges another 35 have been built across Canada since the Headingley pilot project use fibre-reinforced polymers instead of steel bars to strengthen the concrete girders. Fibre-optic sensors measure the strain caused by traffic and report back to engineers or anyone else who is interested through the Internet.

Three types of sensors on the girders under the two-lane bridge on Provincial Road 334 measure vibrations and how much the bridge stretches or compresses when heavy trucks cross over.

Most sections of the bridge were built with conventional technology, allowing ISIS to compare the results for steel-reinforced girders and those made with the new materials.

Mufti said the vibration reading like a person's heart rate should stay relatively steady. If it goes way up or down, the bridge has probably been damaged.

In the past, bridges fell apart without engineers knowing exactly why or how to prevent problems in future designs.
Wires running through pipes carry information from the sensors to a computer in a heated room under the bridge, which analyses the signals and posts results to the Internet.

To see live video images of vehicles crossing the bridge while following the strain changes on a graph, check out the ISIS Web site at 130.179.134.168/LiveDatawithVideoTaylor.html.

After sensors on the Headingley bridge proved the new polymers behave just like steel without corroding as the metal does bridge-builders in Manitoba, Quebec, B.C. and Alberta started building their own polymer-reinforced bridges.

There are now probably more than 500 across Canada, Mufti estimates. About five per cent of new bridges are built with the new materials, but about 70 per cent of repairs to old bridges take advantage of the new technology, he said.

The Golden Boy statue has also been hooked up with ISIS sensors to monitor the strains of living on the dome of the Manitoba Legislative Building.

"You could almost see the Golden Boy was dancing," Mufti said after a windy day this week.

Soon, Winnipeg's new Provencher Bridge will be the smartest in town, able to monitor the effects of temperature and wind as well as traffic. The Confederation Bridge linking Prince Edward Island to the mainland, although not reinforced with polymers, has sensors that measure the jolt if an iceberg hits.

When the concrete on conventional bridges cracks, road salt used to keep surfaces ice-free comes in contact with steel bars embedded in the concrete, causing them to corrode. One lane of the Arlington Street bridge was closed this week after steel in the bridge deck rusted through.

Smart bridges replace the steel with composite materials like those used in new-generation airplane parts manufactured at Boeing's Winnipeg plant.

Fibres made of glass, carbon or aramid (a type of nylon) are embedded in a matrix of polyester or a similar substance to create the new bars.

ISIS, a Winnipeg-based non-profit network involving 15 universities, has indirectly boosted the construction industry. The polymer bars are made in Quebec, but Mufti said a Winnipeg company might get involved as demand rises.

Meanwhile, Winnipeg's IDERS Engineering is manufacturing instruments to read the strain sensors.

"It's a fantastic development," Mufti said. "Hopefully they can market them worldwide."

ISIS's biggest contribution has been to the public purse smart bridges cost about 20 per cent more to build, but their longevity more than compensates for the extra cost.

The technology is also being used to restore historic properties, and Veterans Affairs recently met with Mufti to discuss restoration of granite war monuments, including the one at Brookside Cemetery.

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