Do hidden cracks imperil Bay Bridge?

sacbee.com ^ | Saturday, Jun. 21, 2014 | Charles Piller

[Second Amendment First]

The welding code and construction contract for the suspension-span roadway of the new San Francisco-Oakland Bay Bridge each contain a universal rule: “No cracks.”

That rule applies to any new steel bridge and is particularly important for a “fracture-critical” bridge such as the new span, which opened last fall. Fracture-critical bridges can break, because some of their parts lack redundancy or backup. If a weld crack grows larger, causing such a part to fail, all or part of the roadway could collapse.

In 2008, the no-cracks rule put the California Department of Transportation in a worrisome bind. The Chinese firm hired to build the roadway routinely produced cracked welds that proved difficult to fix. Facing rising costs and increasing delays on a $6.5 billion bridge that was already years behind schedule and billions over budget, Caltrans sought advice about its options from a highly regarded expert in how metal fractures. He said some cracks can remain without compromising safety.

Caltrans then changed its contract and decided to put aside the welding code. Its fracture-critical bridge could now have cracks.

Weld cracks are the latest in the litany of errors and construction problems regarding the new span that have steadily emerged in recent years. Suspect foundation concrete, rusted tendons in the skyway that connects the suspension span to Oakland, broken anchor rods, and corrosion on the main cable are among the issues uncovered by The Sacramento Bee and others.

[BlueMondaySkipper]

I’d be interested to understand why the Chinese had such trouble making decent welds.

Probably hard to weld the crappy Chinese steel using the crappy Chinese welding equipment.

[CodeToad]

“So costs do trump engineering?”

Always, 100% of the time. Petty corporate politics the other 100% of the time. :)

[Political Junkie Too]

So costs do trump engineering?

In this case, opening the bridge by Labor Day last year was most important, otherwise the construction company would lose its bonus for being on schedule.

Cracks or no cracks, good rods or bad rods, the local government made sure that American Bridge/Fluor Enterprises still got its $49 million in bonuses.

-PJ