New York City turns to engineers at ATLSS for help in evaluating suspension bridge cables.

Engineers at Lehigh's ATLSS Research Center are lending their expertise to a study that is attempting to determine the remaining safe life of the cables in five New York City suspension bridges.

An article titled "Studies in Suspense Flourish in New York, published in the Oct. 6 issue of ENR magazine, detailed efforts by the New York State Bridge Authority to "predict if, when, and why cables waken."

In the three-month study, which is led by Modjeski & Masters, engineers are removing pieces of wire from cables to study the effect of loading and environment on the rate of cracking and on fracture toughness. ATLSS engineers are helping evaluate the cracks' shapes under an electron microscope.

"Other studies have focused more on how cracks form," said John Fisher, founding former director of ATLSS (Advanced Technology for Large Structural Systems) and now professor emeritus of civil engineering at Lehigh. "This study is trying to create a better predictive model for fracture crack extension."