Ohio Fastener Manufacturer Scrutinized Over Bolt Failure

April 04

00:00 2013

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FEATURE

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Journalists at the bridge site (courtesy SF Chronicle)

FIN’s Background on Dyson
Founded in 1884 as a specialty forging shop in Cleveland by Joseph Dyson, today Dyson is a ISO 9000 certified manufacturer of fasteners for the nuclear, bridge, mining, military, locks and dams, oil and gas and wind power markets. Dyson provides custom forging, machining, heat treating, inspection and quality control. Dyson manufactures bolts and screws, nuts and washer, rods, studs, pins, construction accessories, specialty fasteners, custom forging and machining to ASTM, SAE, ASME, MIL/Federal, ISO, ANSI, AASHTO and DIN specifications.

Dyson exports fasteners to Europe, Africa, the Middle East, Asia, Australia, Canada and Mexico.

In 2010 Dyson was awarded a contract for bolts, nuts, washers and plate assemblies for the rewrapping of the main cable and hand rope replacement on the rehabilitation of the 1909 Manhattan Bridge. The bridge carries vehicular, mass transit, pedestrian and bicycle traffic.

“With in-plant capabilities that range from open or closed die forging and heat treating, to primary and secondary machining, and strict quality control, Dyson can assure you of unsurpassed quality because we control every facet of the manufacturing process,” according to the company’s website – dysoncorp.com.

See FIN Fastener History:
1988 FIN – Dyson Introduces Traceable Bolts
1984 FIN – Dyson Completes U.S. Navy Construction Requiring Large Fasteners

MEDIA SPOTLIGHT — Days after at least 30 giant bolts on the new $6.4 billion eastern span of the Oakland Bay Bridge snapped, the California state transportation agency has decided to reinspect all 288 bolts provided to the project by an Ohio fastener manufacturer, the San Francisco Chronicle reports.
“The company, Dyson Corp., has made or supplied a variety of bolts, fasteners and other parts that have gone into construction of the $6.4 billion bridge, which is scheduled to open to traffic the day after Labor Day,” writes Jaxon Van Derbeken of the Chronicle. “They include 4-foot-long, 3 1/2-inch-diameter rods that secure the cables on the span’s single, signature tower.”

While no final determination has been made, the problem appears to be related to hydrogen embrittlement.

“Caltrans acknowledged Monday that earlier tests performed on some of those galvanized-steel bolts had raised questions about their ability to stretch during an earthquake, but that agency engineers had approved them anyway,” according to the Chronicle.

“Caltrans did not test the bolts for the problem that it now believes caused them to fail – the presence of hydrogen in the steel, which can make the bolts brittle. Officials assumed that the potential for contamination had been eliminated during the manufacturing and galvanizing process.”

The Chronicle noted that “Dyson did not make the steel, but was in charge of the process and conducted its own testing.”

The issue reportedly was discovered in March when construction crews began tightening the nuts on either end of 96 bolts, the Chronicle reports. Days later the crews found that “one-third had popped loose, damaging the bolts.”

Caltrans has ordered inspection of all the bolts — which range from four feet to 17 feet with a 2.5 inch diameter — before the new bridge opens on Labor Day, according to the Chronicle. The cost or length of repair has not been determined.

One alternative the agency has discussed is installing a steel collar around the seismic-stability structure where the bolts failed and clamping it down with new bolts. Replacing the brittle bolts is all but impossible because they are covered by the eastern-span roadways.

Editor’s Note: Articles in Media Spotlight are excerpts from publications or broadcasts that show the industry what the public is reading or hearing about fasteners and fastener companies.

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