The record-union., 1896-08-06
IN A WRETCHED CONDITION.
The Bridge Over the American River
Near This City.
Report Of Experts Robinson and Fall
coner- Repairs Or.
dered Made.

AT yesterdays session of the Board
OF Supervisors Engineer Robinson and
Expert Falconer, who had on the pre-
ceding day made an inspection of the
American River bridge, at the request
of the board, submitted their report.
The purpose of the inspection was to
determine whether or not Darby Lay
don had correctly represented the con-
dition of the bridge ard the extent of
the repairs required to make it perma-
nently safe.
The examination made by Messrs.
Robinson and Falconer show that the
structure is rapidly decaying in places
and that immediate and extensive re-
pairs are necessary in order to save it
and to make travel over it safe. Fol-
lowing is
THE REPORT:
SACRAMENTO, Aug. 5, 1S96.-To
the Honorable Board of Supervisors,
Sacramento County-Gentlemen: We,
the undersigned, have made a careful
inspection of the highway bridge over
the American River, north of Twelfth
street, Sacramento. The bridge con-
sists of three spans of double inter
section, combination wood and iron,
9Tdtl ITuSSeS, O1 ZtO I6eC Gdcn
The spans are all in very bad and un-
safe condition, and all loads should be
restricted to a weight of not more than
5000 pounds, including team and
wagon, at a very slow speed, pending
repairs which are absolutely necessary.
The temporary bents which are placed
under the centers of each span are in
no way a support to the span in gem
eral. They carry only the load which
Is concentrated directly over and trans
mitted through the panels, which are
supported by them, and no more. If
properly braced, the bents would be of
great service in taking care of a por-
ton of the lateral vibration, which,
owing to defective construction of low
er lateral system, is very alarming.
The defect in the lateral system con-
sistS in there being no rigid connec-
items laterally of the floor beams, which
also act as struts With the bottom
chord pins, to which they are hung by
yokes, which are free to slip along the
pins from side to side between the
chord bars, and consequently do not
hold the trusses in line. The center
span is not provided with expansion
rollers at either end, and in conse-
quence the piers are either forced to
move enough at the top to allow for
variation in temperature, or distortion
OF the truss must take place. which in
creaseS the tension and compression
n the members affected to an extent
that must eventually lead to destruc-
ten through over -straining. The ex-
pansion rollers on the end spans are
rot in position, and are choked and
clogged with dirt and rust so that the
bridge can move only by sliding over
them. The top chords in all spans are
badly distorted, and it will be neces-
sary to renew quite a number of Sec
uons-the number depending on the
condition of the ends where they come
III contact with the intersection cast
1ngs of which a number are crushed,
The number of sections to be renewed
can only be determined after the bridge
IS on false work and the chords taken
apart Many of the other compress
sion members in the truss are defect
i've, and though some of them might be
safe for a year or SO. they should be
renewed with those that are absolutely
re cessary, and thus avoid the expense
OF placing false work under the spans
again in the near future. The top lat
eral system should be overhauled, and
some new timber substituted. in order
to frame in proper manner to hold the
top chords in line, which the present
system fails to do.
The entire floor should be replaced
with one or lighter material, in order
that the truss members be not over
strained with the combined excessive
dead and live loads which they are now
compelled to carry. The floor beams,
many of them, are badly rotted, and
others are crushed on the ends by the
lateral rods. The washers on these
rods are entirely too small, and should
be replaced with larger ones so that
they viii not crush the wood again
We would recommend that a sleeve or
clamp be put on the pin each side of
the yoke which carries the floor beams,
thus keeping the yoke in the center
OF the pin, so that the strain on the
rods will be equal At present these
yokes have slipped over near the end
of the pin, and one rod is practically
carrying all of the load
In view of the fact that the traffic is
very heavy over this bridge, it will