Close

Search

Search Menu
Photonics Media Photonics Buyers' Guide Photonics EDU Photonics Spectra BioPhotonics EuroPhotonics Industrial Photonics Photonics Showcase Photonics ProdSpec Photonics Handbook
More News
SPECIAL ANNOUNCEMENT
2016 Photonics Buyers' Guide Clearance! – Use Coupon Code FC16 to save 60%!
share
Email Facebook Twitter Google+ LinkedIn Comments

Terahertz Source Inspects Bridge Components

Photonics.com
Dec 2015
SENDAI, Japan, Dec. 14, 2015 — Terahertz waves could be especially useful in the safety inspection of bridges that use prestressed concrete (PC) steel wires hidden inside external cables covered by resin jackets.

That's the conclusion of researchers at Tohoku University who developed an optical measurement system able to penetrate polyethylene resin and similar resins. This allows nondestructive imaging of the inside of PC steel wire without removing the resin cover, as the terahertz waves efficiently reflect off metal surfaces within the resin.

Comparison of a photograph and a terahertz image of a prestressed concrete steel cable.
Comparison of a photograph and a terahertz image of a prestressed concrete steel cable. The polyethylene outer mold was partially removed. Courtesy of Yutaka Oyama.

External cables are important structural elements for dispersing loads in extradosed bridges, which are cable-stayed structures usually featuring a box girder deck. Resin coatings also make external cables resistant to corrosion.

Destructive inspections of the cables, in which the outer coating is removed from the cable, run the risk of allowing moisture to penetrate the wires and corrode them after the inspection has been completed.

Results of this research were presented at the CLEO Pacific Rim conference held in earlier this year Busan, South Korea.


GLOSSARY
metrology
The science of measurement, particularly of lengths and angles.
Comments
Terms & Conditions Privacy Policy About Us Contact Us
back to top

Facebook Twitter Instagram LinkedIn YouTube RSS
©2016 Photonics Media
x We deliver – right to your inbox. Subscribe FREE to our newsletters.