Tip:
Highlight text to annotate it
X
CLOSED AS A PRECAUTION.
>>> BAY BRIDGE SAFETY CONCERNS
STILL UNFOLDING TONIGHT.
WE ARE NOW LEARNING MORE ABOUT
WHY THOSE 32 ANCHOR RODS MAY
HAVE BROKEN ON THE EASTERN SPAN
OF THE BAY BRIDGE.
CHARLES CLIFFORD HAS AN UPDATE.
>> Reporter: CALTRANS IS SAYING
THEY SUSPECT AN EXCESSIVE
AMOUNT OF HYDROGEN SEEPED INTO
THE RODS EVENTUALLY CAUSING
THEM TO BREAK.
THE QUESTION IS HOW DID THE
HYDROGEN GET INTO THE STEEL.
ON FRIDAY, CALTRANS
RELEASEDDETAILED INFORMATION
DESCRIBING THE FABRICATION,
GALVANIZATION AND TESTING OF
ALL 288 ANCHOR RODS.
AFTER SCANNING THROUGH THE
MATERIAL, THERE'S NO APPARENT
EXPLANATION FOR HOW AN EXCESS
AMOUNT OF HYDROGEN MAY HAVE GOT
INTO THE METAL.
THE DEVIL IT SEEMS IS IN THE
DETAILS.
THERE ARE A COUPLE
POSSIBILITIES.
DURING FABRICATION OF THE
BOLTS, THE METAL IS HEAT
TREATED OR BAKED TO MAKE THE
RODS STRONGER.
THIS PROCESS MAY HAVE
STRENGTHENED THE STEEL, BUT
LEFT IT VULNERABLE TO HYDROGEN.
THE RODS ARE GALVANIZED OR
COATED WITH ZINC TO KEEP WATER
AWAY FROM THE METAL.
POOR QUALITY GALVANIZATION MAY
HAVE KEPT THE STEEL EXPOSED.
THE BOLTS BROKEN WERE INSTALLED
YEARS AGO BUT ONLY RECENTLY
TIGHTENED DOWN.
DURING THAT TIME, RAIN WATER
MAY HAVE SEEPED INTO THE METAL
MAKING THE RODS BRITTLE.
CALTRANS WOULDN'T SAY IT ANY OF
THE SCENARIOS OR SOME OTHER
CAUSE LED TO THE 32 BROKEN
RODS.
>> WE DO KNOW THERE IS
HYDROGEN.
THERE IS AN EXCESS OF HYDROGEN
IN THE STEEL BOLTS.
AT WHAT POINT THAT HYDROGEN
CAME TO BE IN THE STEEL BOLTS,
WE DON'T KNOW.
THAT'S WHAT THE INVESTIGATION
IS LOOKING INTO.
>> Reporter: IN THE MEANTIME,
TESTING CONTINUES ON THE