A Bridge Mob Scene

Editor: Based upon the bridge rating analysis recently completed
by the engineering firm selected by our city staff, a “bridge mob
scene” equal to 10% of our city’s population will commonly assemble
on our Memorial Bridge at the same time as it is being crossed by
four, 36 ton, 3-axle trucks. It’s clearly up to that engineering
firm’s technical judgment to determine how many assembled
pedestrians they consider to be a probable and reasonable weight
load on our bridge for rating purposes.
According to their “considered” judgment, that number is about
1200. This is equal to 2 lines of Healdsburgers on each bridge
sidewalk; elbow-to-elbow and stomach-to-back pocket standing on our
bridge at the same time it is being crossed by four, 36 ton, 3-axle
trucks – a claimed “probable” occurrence.
So why would anyone propose this incredulous condition as a
“probable and reasonable” load on our bridge? One possible answer
to that question could be the following. The structural rating of
our bridge drops as the assumed weight load is increased. If it
drops low enough, then the bridge becomes eligible for the federal
funding of a replacement bridge. Otherwise, only rehabilitation
funding is available.
Of course, that is just a possible answer. You will have to
judge for yourself if that is a plausible answer.
When the same rating calculation was done by Caltrans in 1979,
they assumed the pedestrian load to be zero. When Caltrans redid
the calculations in 2008 which resulted in their lifting of the
long standing (27 years) load limits on our bridge, they used 600
pedestrians. Not to be outdone, the engineering firm recommended by
our city staff doubled that to 1200. The director of our Public
Works department has declared the 1200 number to be
“non-negotiable”.
Not surprisingly, with that lowered rating, our bridge now
qualifies for federal bridge replacement funds.
Fortunately, in the final analysis, the future of our Healdsburg
Memorial Bridge will be determined not by an outside consulting
firm, an arcane bridge rating number or by a member of our city
staff but by the informed and collective judgment of our elected
city council members.
If you support the rehabilitation and preservation of the
historic and iconic entry to our city, please attend the open house
from 5:30 to 7:30 p.m. on Thursday, April 29 at our Senior Center
(1/2 block east of our downtown Plaza).
Let your voice and concerns be heard and recorded. The future of
our Memorial Bridge depends upon it.
Mel Amato
Healdsburg