The in basket: It appears to me that the new Tacoma Narrows Bridge’s car deck is a good 10 feet higher than that on the existing bridge. The bridge engineers have alerted reporters in several previous instances that the initial appearance of some bridge components would change as the work progresses. I asked if this is another such instance.
The in basket: It appears to me that the new Tacoma Narrows
Bridge’s car deck is a good 10 feet higher than that on the
existing bridge. The bridge engineers have alerted reporters in
several previous instances that the initial appearance of some
bridge components would change as the work progresses. I asked if
this is another such instance.
The out basket: Claudia Cornish of the state bridge office said
yes, the level of the deck of the new bridge will drop as it is
finished. The weight of welds, bolts, a waterproof membrane, the
asphalt driving surface and two jersey barriers will force it
lower. “Some elongation (‘stretching’) will occur on both the
suspender cables
and the main suspension cables as weight is added to the bridge
deck,” she said.
Not only will it eliminate the greater height of the new deck, it
will leave it about a foot and nine inches lower than the existing
deck, she said.
“The elevation differences change a little depending on where
you’re standing
on the deck, but that’s a good average,” she said.
Incidentally, a decision on the amount of the toll when the bridge
opens this summer has been put off by the state Transportation
Commission, which will make that decision, until the Legislature
has decided whether to contribute any more money to the project,
says Janet Matkin of the toll office.
