Daily capital journal. (Salem, Oregon) 1903-1919, 1915-11-22
STEEL BRIDGE SAFE
FOR A LIMITED LOAD
SAYS MORSE REPORT
Bridge Expert Confirms Con.
/. clusiOns Of State Highway
Engineers

The steel bridge across the William
cite river at this place will be safe
for light loads if the present repairs
are completed, according to the report
of Henry Morse, the western represen-
tative of Ralph Modieska, who made
an examination of the bridge recently
and today submitted his report to
Cantine. The report of Mr. Morse con-
firms the previous reports of the state
highway department engineers, Holmes
and Sadler, and also states that the
load limit should not exceed 1000
pounds which they stated in their re-
port to the county court last month.
cludes the weight of the team and the
The 1000 pound load, however, in
eludes the weight of the team and We
hicle or the truck and it is estimated
that any net load of over 1000 is un-
safe on the bridge.
All of the calculations are based
upon the supposition that the steel of
the bridge has not deteriorated any
more than it appears to the eye of an
engineering expert and does not in
clude any laboratory tests. History of
the past has been that bridges fail
when least expected after they have
reached their limit and Mr.. Morse says
the Salem bridge has now outlived its
usefulness. The report of Mr.. Morse
was requested by Mr.. Cantine who
wished to remove any ideas in the
minds of the people of Polk ana Ma
ron county that new bridge was be.
ing advocated while there was any SER
vice in the old structure. The engin-
eering department recommends that
the bridge be closed during a hieh
wind or after any great change in
temperature.
The repairs now going on will be
completed this week and in addition to
the bracing of the cords and struts the
lateral system will be strengthened.
The repairs, however, will still cost
less than $4,000 though they will ex.
ceed the estimate of $13O0 as first
| given out.
After a consideration Of the results
obtained by the computations and of
the conditions observedl Mr.. Morse
makes the following conclusions.
/. That the life of the bridge has
practically reached its limit and taat
failure may take place under certain
conditions Of loading which may be
imposed upon it at any time.
z. That an attempt to prolong its
use except to the extent of rendering
it reasonably safe for temporary means
of crossing until it can be replaced by
q new structure, would not be justified
either from the standpoint of safety OF
economy.
3. That temporary safety demands
That in addition to the repair worl,
which has been begun as outlined by
your department, additional reinforce.
ments be made in the lateral systems
The lateral rods extending through two
panels and beginning at the third panel
point from the ends in the lower sys.
TEN, should be replaced by bracing in
each panel, preferably of angle section
rlvited to floor beams at the pin points
Of lower chord. Compression struts
which might be Of wood, should be in.
troduced longitudinally Of the truss
at the end connections of these later.
ais between pin points to serve as stiff
eners to the suspended floor beams 10.
Gated at the points of panel subdivi
sion.
Beginning at the hip joint the later.
ais in the top system should be replac.
cd in similar mdnner by bracing, ex
tending over one panel instead of two
as at present, for the first four panels
from each end. In the remaining pan
els Of both systems the present laterals
should be properly adjusted to do theil
work.
4. That, while these reinforcement.
will greatly reduce the liability to o
collapse Of the structure under Sc
we're wind, they can not be expected
to remedy entirely the vibration whicr
is caused in this bridge by both wind
and traffic. II is this vibration anc
the continual racking to which tho
structure is subjected by reason Of iii
light construction and proportion oil
its members, that carries the element
Of danger at all times. Warnings oil
failure are generally given, however
in time to prevent loss of life, there
from, provided they are intelligently
watched for. To reduce the chance OF
calamity to minimum, therefore IL Il
Imperative that n periodical inspection
be made by a competent bridge man n
least every sixty days under ordinar,
conditions, and at such special times o.
am unusually severe storm or wild,
change of temperature might require.
8. That with every precaution tai;
, en- as outlined above, considering tn
fact that tnis bridge is the only mean
Of crossing the river in the vicinit,
and seryies large territory, .shoul
consider the authorities justified II
keeping 1t open to traffic under th
present restrictions, which should, O
course, be rigidly maintained until
new bridge can be constructed, or m
til signs Of immediate danger are man
tested in the meantime