UBC Reports | Vol. 47 | No. 16 | October
Spray strengthens structures
Application prevents corrosion and contamination
by Michelle Cook staff writer
A UBC civil engineering professor is testing a revolutionary polymer
spray that is expected to double the strength of aging bridges at
half the cost of traditional repair techniques.
Prof. Nemkumar Banthia developed the high performance fibre reinforced
polymer (FRP) spray being used on Safe Bridge near Duncan.
He and a team of UBC students and researchers, with engineers from
the B.C. transportation ministry, applied the spray to the 46-year-old
bridge over a period of five days. The ministry committed $60,000
to test the new technology on the six-metre bridge with a view to
using it for future infrastructure repairs.
The spray coating, composed of separate components of fibre and
polymer applied at high-speed, is a novel structural rehabilitation
technique designed to protect the bridge's concrete girders from
corrosion, increase the structure's longevity and protect it against
"The spray application was very successful," says Banthia. "After
the facelift, the bridge should be twice as strong and be able to
absorb three times as much energy during an earthquake."
With its new FRP coating, Safe Bridge is now a "smart" bridge.
Both the structure itself and the polymer coating carry fibre-optic
sensors that transmit data by the Internet. These signals will help
Banthia and his team to monitor the coat's effectiveness from campus.
The data will also allow engineers to study the bridge's performance
in an earthquake and, afterwards, use the sensors to assess any
damage to the bridge.
In lab tests against existing repair techniques, the FRP spray
coating proved to be the strongest method of bridge deck repair.
The technique is estimated to cost half the amount of traditional
steel jacketing and a third less than fibre-reinforced polymer jacketing.
Unlike steel jacketing, which corrodes over time, FRP spray will
not corrode, adding to long-term cost savings, but Banthia explains
that the real savings will be in the minimized repair times and
The versatile repair technique lets the user control the fibre
content making it ideal for refitting other construction surfaces
such as steel and timber, and customizing the repairs on any structure.
Besides strengthening, FRP spray can be used to prevent corrosion
in high chloride environments such as the Hibernia oil drilling
It can also be used to protect water supplies from contamination
by creating an impermeable lining for containers like hog waste
The FRP spray and application technique was developed in conjunction
with Intelligent Sensing for Innovative Structures (ISIS)
Canada, a Network of Centres of Excellence program headquartered
at the University of Manitoba.