Bay Bridge technicians 'listen' for cracking in the steel anchor rods (CalTRans at its finest)

Mercury News ^ | 5/6/13 | Lisa Vorderbrueggen - Contra Costa Times

[NormsRevenge]

OAKLAND — Strategically positioned high above the water, in a narrow crawl space between the new Bay Bridge deck and the top of its big pier east of the tower, instruments are listening for the sounds of cracking inside steel anchor rods.

Caltrans placed 10 acoustic emission sensors on select rods in early April after some of the massive bolts -- 3 inches in diameter and 17 to 24 feet long -- snapped and triggered widespread worry about the replacement eastern span's seismic safety.

The instrument records the energy produced when a crack initiates, spreads or moves within the rod, said Caltrans materials engineer Bahjat Bagher, who showed off the testing late Friday. But so far, the rods being tested are quiet, a great relief to the agency.

If the bolts -- fabricated in 2010, two years after the 32 bolts that broke -- were also faulty and had to be replaced, the cost to make the $6.4 billion bridge safe for motorists would rise, and Caltrans would face an even greater hurdle to opening the bridge on time.

A second test for hardness is also showing favorable results, although a third saltwater corrosion test is still to come.

"We are pretty confident that we don't have an immediate failure issue with these bolts, but we want to have a strong level of confidence over the long-term," said Toll Bridge Program Manager Tony Anziano.

It's small a piece of good news amid mounting concerns about the $6.4 billion span's ability to withstand the next big earthquake. The long, hefty anchor rods tie the bridge deck and pier columns to the shear keys and bearings that help control sway and uplift during a quake.

[Spartan302]

oops, meant inch and a half.

[ken in texas]

You can see it but you’re not strong enough to lift it. :)

[Veto!]

Affirmative Action and sub-standard materials on a bridge project.

Thanks for the info. Sounds like a recipe for disaster.

[Lurker]

Note the gap on the center one. It should be snug against the plate.

[superfries]

the blue is where it was before it went bad...then they did not back it off they tried to tighten it back down further and it is still not tight because it is broken.