Daily capital journal. (Salem, Oregon) 1903-1919, 1914-08-04
HIGHWAY ENGINEER
CONDEMNS BRIDGE
Says It Has Gotten Beyond Profitable
Repair and New One Is Only Way
to Fix It.

That the steel bridge across the Will
lamette river at the end of Center
street is carrying loads that 1t cannot
be depended on to carry with failure,
is the gist of report submitted by
State Highway Engineer II. L. Bowlby
at the request of the county courts of
Marion and Polk counties and the city
of Salem. There is no question but
that the bridge is unsafe, according to
Mr.. Bowlby, but he gave it as his opin-
ion that by limiting the traffic to single
concentrated loads of five tons at one
time and reducing the speed to not
more than four miles per hour across
the bridge that the element of danger
would be lessened but not eliminated
entirely.
1t was explained that old bridges in
the condition of this one often acted
peculiarly and that heavy load might
pass over the bridge in safety and then
the bridge might fail under q much
lighter load. The vibrations of the
bridge are excessive at times as shown
when the company of regulars, company
E Of the Twenty-first infantry, crossed
the bridge. The company was in sin
gle file breakstep, yet they were COM
PEELED to halt three times in crossing
the bridge on account of the vibra.
tions. The shoes, or rollers, placed Oh
top of the piers so that the bridge may
I slide when heat and cold contractions
and expansions change the length of
the structure, have rusted so that they
do not move. As a result the piers
are moved when the bridge changes its
length 1t is likely that this effect has
impaired the stability Of the piers.
The log of inspection shows that
many of the joints are rusted between
the plates and pitted, braces are warped
and in bad condition and that deep rust
patches show through tne structure. The
top chord is sagged. struts are bent
and that the braces admit Of excessive
play in all directions
The summary of the report and the
recommendations Of Mr. BOwlby are as
Follows:
Practically the entire deck of bridge
is in need of replacement. Posts
throughout trusses are deeply pitted
and rusted below level of deck OF
bridge. Posts on south side Ut bridge
show more effects of rust than on north
side. All shoes on the south side OF
botn trusses show unusual deterioration
from rust. Shoes on north side of
bridge, while rusted and pitted. do not
appear as bad as ON the south side
Gusset plates connecting lower laterals
at shoes are almost rusted off All la.
terals are very loose. Cover plates of
top chords show rust and are pitted
deeply; between cover plates and con
Meeting gusset plates of top lateral sys.
TEN, rust has eaten in quarter Of an
inch at some connections. Most of the
posts of the trusses are sprung out due
to the distortion of the truss by eleva.
tion at center pier. Actual distortion
shown on sketch of three panels of north
truss of east span Vibration under all
loads is excessive in all directions. The
trusses nave sagged between the center
and end posts as shown on schedule at.
tached. The shoes no longer act on the
rollers, thus the piers have been pulled
back and forth as length of spans
changed.
The matter of either building a new
bridge, condemning the old one or put
ting in ferry will be taken up at a
joint meeting of the county courts OF
Marion and Polk counties next Wednes
day with the street committee of the
city council.
AS Engineer Sees 1t.
From the calculated stresses. based
on the loads the bridge is now called
on to carry, and the condition of the
metal, the bridge is carrying LOADS
that it cannot safely be depended on
to carry without failure.
For instance, combination of a
hlgn wind and two heavy trucks passing
at moderate speed, with the average
vehicle load on the bridge, would be q
combination that the bridge would have
difficulty in carrying, owing to over.
stressing of the hangers and laterals.
- From the enclosed traffic schedule
and speeds observed, the necessity OF
reducing this speed to about four mile,
an hour, by setting a time limit under
which no vehicle shall cross tine bridge
under penalty, is apparent. The bridge
has reached a state where any genera
plan of repairs that will not be waste
of money is impossible
CHTEF TTTGTTNE npAn