Hawk Measurement Systems

Smart Sensor Technology for Bridge Health

Structural Health Monitoring of Bridges

Bridge health is an important issue• Bridge collapses often result in a large number of casualties, as well

as negative social and economic consequences.

• I-35W Mississippi River Bridge near Minneapolis collapsed on 01/08/2007. 13 people died and 145 were injured.

Life span of highway bridges is ~70 years• An MIT estimate says, over the next few years, costs for repair and

refits amount $ 600 billion a year

• Structural health monitoring can mitigate problems

Conventional Monitoring Systems

Expensive

• $4,000-15,000 per sensor using wired devices

• $600 per sensor using wireless devices

Point sensor

• Each sensor can only monitor one spot and one parameter

Regular maintenance is costly and necessary

Every sensor needs to be powered

Bulky

Recently Developed Wireless Sensors

• 71 wireless sensor nodes

with a total of 427 sensing

channels were installed

on the girder, pylons, and

cables in 2009 to monitor

cable tension force,

temperature and dynamic

instability to determine

structural performance

and find possible damage

locations.

• Wireless sensors also

have the disadvantages

of conventional sensors.

The second Jindo Bridge in South Korea

Subheading:

• Dot Point

• Dot Point

• Dot Point.

Fibre Optic Sensing

• Distributed sensor can continuously monitor vibration, strain and temperature on structural elements of the bridge for the entire length of optical fibre.

• Fibre optic cable is easy to install.

• Fibre optic cable is passive – No electrical power required.

• Little or no maintenance required.

• Fibre optic sensing has low cost.

Fibre Optic Sensing Suits All Types of Bridges

• Stress, strain along tensile members and cables

• Compressive strain on support columns

• Vibration and resonance effects

• Emergence of cracks

• Movement of joints and hinges

• Temperature

• Deflection of beam, arch and truss etc.

Types of Distributed Monitoring

On-site fibre optic sensor gluing procedure (left) and

installed fibre optic sensor (right)

Thank You!