The critical deterioration of transportation infrastructure across the world, 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.

Researchers 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 -- lightweight 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 Healingly, Manitoba is outfitted with 66 fiber optic sensors. The instrumentation in the Healingly 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.

Fiber optic sensors used in smart structures.

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.

The application of smart structure for bridges provides benefits:

1. Less time and expenses in inspections.
2. The response of the structure can be monitored remotely in real time. 
3. Performance of the new advanced composite materials can be monitored.
4. The long-term performance of advanced composite materials can be compared to conventional girders in the bridge, also outfitted with fiber optic sensors.

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