The Owosso times. (Owosso, Mich.) 1897-1926, 1898-04-01

the river. When public health demands that it
be disposed OF elsewhere you will be compelled
either case pumping will be necessary. You can
pump from that point as well as from Oliver
street. You are nearer manufacturing plants
and can use compressed air for power at less cost
than you can install steam and further force main
Is cheaper than gravity main.
bed Of the stream win probably be necessary in
case you build this sewer, whether you make
the outlet at Shiawassee street or lower down.
The proposed change, therefore,. appears to
me feasible and desirable. Respectfully,
Fl. K. RIGGS, Engineer.
The mayor appointed as special committee
to settle with the treasurer, Aids. Walsh and
Clerk presented following report which was
upon motion received and referred to a special
committee heretofore appointed by this council
consisting of Aids. Copas and PerrigO.
To the Honorable Board of Councilman, Owosso,
Gentlemen-Complying with the directions of
your bridge committee have made very care
of the Main street bridge over Shlawassee river,
In your city, and after computing the strains up
on each member under such traffic as 1t is likely
to be called upon to carry at any time, and after
a very careful consideration of the important
question from every standpoint. / have sent you
the following message and now beg leave to con-
Bridge unsafe for heavy loads which are like
ly to come on at any time; IL cannot be stihened
bridge. My full report later"
Such Is my Judgment after thorough study of
s Which % each One
clusiOn, / beg leave to submit the following state
ment of facts as found them. viz:
The bridge i'm question is of the type known as
a Whpple wrought iron truss, also known as a
double Intersection Pratt truss. 1t was built by
the Wrought Iron Bridge Co. of Canton, Ohio, in
1876 and Is therefore fore nearly % years old 1t
found on infrequenty travelled country roads,
and Is not at all adapted to the heavy traffic of
prosperous little city like Owosso
II Is nine panel structure 1872 feet between
centers of end pins. 1t has twenty-foOt clear
roadway with fve-foot sidewalk outside of each
truss 1t has stone abutments which show signs
of weakness in the several cracks which appear
In the masonry.
mansions of the various members which enter
into the construction of the bridge, made note
of the following defects to which / beg to call
your attention, viz:
or two places, and is liable at any time to let
some one into the river, and besides its connec-
ton with. the floor beam Is weak In design.
2. There are numerous rotten jOistS In the floor
system.
8. Each and every strut in the top lateral sys-
tenn is bowed (sOme badly, caused doubtless by
screwing up the tension rods too tight and by
inherent weakness In the design Of the struts.
In their present condition they are of little utility
tenn are also bowed, from similar causes proba-
bly,; and these very important members are thus
incapable of giving their best service.
5. Much of the field work was bolted work in
stead OF rveted work. and as a consequence
noticed that some of the nuts were missing.
6. There are five separate bad scaly cracks In
the cover plates of the top chords which indicate
metal of very poor quality and of little strength.
Z. The passage of heavy loads while l was ex-
aiming the upper works caused much swaying
and vibration, indicative of weakness of design.
This was particularly noticeable during the pass
age of a coal truck and again during the passage
OF heavy load OF lumber. The electric car pass
ed frequently but was not loaded and did not,
therefore. strain the bridge as much some of
the loaded trucks.
The traffic over this bridge is unusually heavy.
as indicated by the statement made to me that
the floor has to be renewed every year and some
times more frequently.
In the calculation of the stresses have as
sumed live or moving load of one hundred (100)
pounds per square foot of floor area. also a con-
centrated load due to the presence of las people
on the electric Car, which has an extreme wheel
base of rs feet inches -,
This loading developed stresses in the various
members of the structure far beyond the limits
of safety.
The floor beams are particularly weak. as also
are the stirrup suspenders connecting them with
thu, pins of the lower chords, and should they
fail IL would be without any warning such as
might be given by other members of the struc
ture.
The various truss members are too light and
the scaly cracks In the cover plates OF the top
chords excite grave suspicion as to the quality
and strength or the materials which were used
in the original construction.
1t is certain that the bridge went through the
mills and shops without inspection which is the
chief cause of the alarming number of highway
bridge failures in this country. A municipality
is guilty of criminal neglect which does not in
sure the careful inspection of the manufacture
of structures on which the lives of its citizens are
daily entrusted.
And so with all the evidences of weakness be-
fere me could not do otherwise than condemn
the bridge and advise you to order new one.
Were the weak points In the bridge confirmed to
a few members 1t might be wise to undertake to
stitfen it in some WV For example, If the floor
beams and hangef Only were weak, new ones
might be made substituted for the old ones;
but this would q strengthen the floor and thef
rest of the stra' Yre would not be benefited.
bridge IL onS as strong as its weakest park
and inasmuch as every member in this particular
bridge is weak, your only alternative is to replace
1t with new one properly designed Throughout
to carry the heaviest traffic which is likely to
come upon 1t.
1, therefore, would respectfully urge your hon.
0rable body to take action looking to the imme-
date construction of new bridge, and mean
while see to it that riding or driving over the
bridge faster than walk Is strictly prohibited,
and chat excessive loads are not permitted to
pass over the structure at all.
Trusting this report will give your honorable
body the Information you desire, remain,
w. j. SHERMAN,
Bridge Inspector.
Upon motion council adjourned until Wednes-
day evening, April @.