Tacoma Narrows Bridge
The Tacoma Narrows Bridge has a long and interesting history.
Its collapse in 1940 led engineers to examine wind loads and aerodynamics when
building such large projects in the future. The bridge opened up the Olympic
Peninsula, and especially the
Gig Harbor area to development.
It also serves as a primary link to
Bremerton and the
Puget Sound Naval Shipyard. However, traffic loads now exceed the 4 lane,
no shoulder, no median bridge. So in the 1990's a public-private partnership,
the first in the state, was set up to build a second bridge, refurbish the
first,
expand SR 16 with carpool lanes, and charge a toll to cover construction costs.
The new bridge and associated projects have been completed as of 2008. The addition of tolls, especially being run by a private company,
have led to many legal battles primarily from Gig Harbor residents. However,
the legal issues were resolved or dismissed a couple years ago and construction
commenced. See my thoughts below for more about these battles and the tolling
process.
The first Tacoma Narrows Bridge was built in the late 1930's to
bridge a narrow strip of Puget Sound between Tacoma and the Olympic Peninsula.
The original bridge was designed to established engineering standards, which called for a stiffened, inflexible structure. However, it was soon discovered that in the Narrows, the wind caught
this stiffened bridge and made it act like an airplane wing. The bridge would
bounce up and down, giving it the nickname "Galloping Gertie".
In November of 1940 a large windstorm blew through the Narrows.
The bridge bounced up and down enough that it was closed to traffic. Soon afterwards
the forces acting upon it became too great and the bridge tore itself apart,
dropping the center span into the Narrows. It was rebuilt a few years later,
now with very prominent holes in the decking and towers to allow for airflow.
The bridges destruction led to the analysis of aerodynamic forces affecting
major construction projects and is still discussed in civil engineering classes
today.
Interesting
Facts:
- Destruction of the first bridge led to the examination of
aerodynamic forces on major civil engineering projects.
- New bridge will have the capability of being second-decked,
either with more traffic lanes or for light rail/Bus Rapid Transit in the future.
- The Tacoma Narrows is a
big shelf between the upper and
lower parts of Puget Sound. Because of this, currents can be up to 8 knots in
the work zone during tidal changes
Thoughts:
While I understand the pain of having to pay a toll everyday to
cross from the Gig Harbor side into Tacoma, and the understandable concern
about a private company running this project, and possibly raising future tolls, the
current tax climate in the state does not allow for public funds to build a
project like this. And the current traffic on SR 16 is almost as bad as on SR 520,
with backups extending miles in both directions for hours. One issue is that the
Gig Harbor area did not become popular until after the first toll was removed.
So yes, I could see a slight drop in property values in the near term, but I
think over time it will enhance property values by allowing faster access. I
also think tolls, already a standard for many years back East, will become the
standard out here as revenues dwindle.
Since the bridge has opened traffic backups have significantly dropped. What could have been a hour or more of sitting in traffic has now moved to just a few minutes. The only choke point currently is the SR 16/Interstate 5 interchange, which is currently being rebuilt.
Links:
Photos © Ben Brooks
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