The Twin Falls times. [volume] (Twin Falls, Idaho) 1905-1916, 1913-09-12

| eAAAouAI VI Clcdu water, Tree from al
kan or other impurities will be added
10 thoroughly wet the mass. No con-
crete or mortar shall be "retempered"
or remixed with additional water af-
ter 1t has partially hardened
The concrete shall be deposited in
layers not exceeding one foot in thick
ness, and each layer shall be deposited
before the previous one has set. If it
is found necessary to allow a period
| or more than one hour to intervene
between the placing of two layers of
concrete, binder or tie of steel rods
or other suitable material must be
provided to insure perfect union in
the concrete
Care shall be taken in depositing
the concrete in forms that all gravel
shall be pushed away from the finish
| ed surface of the abutments, leaving
neat cement finish on the exterior
surface next to the form, on that part
OF the work which shall be exposed to
view
FORMS. The form lumber used on
all surfaces that are to remain expos
ed to view must be planed on the
surface in contact with the concrete
STEEL. All steel used in the con-
struction of this bridge shall con-
form to the manufacturers standard
specifications, as published in the
1903 Hand Book of the Carnegie Steel
Company.
All steel work shall be manufacture
ing according to the practice in effect
in the best American shops.
J DETAILS. All the connections and
details of the several parts of the
structure shall be of such strength,
that upon testing rapture will occur
in the body of the members rather
than in any of their details or con-
nections.
Preference shall be had for such de-
tails as shall be most accessible for
inspection, cleaning and painting; no
closed sections will be allowed.
The pitch of rivets in all classes of
work shall never exceed 6 inches, or
sixteen times the thinnest outside
plate nor be less than three diameters
of the rivets
The rivets used shall generally be
rs, q and h inch in diameter
/ The distance between the edge of
any piece and the center of the rivet
holes must never be less than one ql
inches wide; when practicable, it
rivet.
For punching, the diameter of the
die shall in no case exceed the dia-
meter of the punch by more than one
sixteenth (1-16) of an inch, and all
holes must be clean cut without torn
or ragged edges.
All rivet holes must be accurately
spaced and punched SO that when the
several parts forming one member
are assembled rivet one sixteenth
0-16) of an inch less diameter than
the hole can generally be entered hot
into any hole without roaming or
straining the metal by drifts" occa-
sional variations must be corrected by
roaming.
The rivets when driven must COM
pletely fill the holes. The rivet heads
must be round and of uniform size
for the same sized rivets throughout
the work. They must be full and
!, neatly made, and be concentric to the
rivet hole and thoroughly pinch the
connected pieces together.
Wherever possible, all rivets must
! be machine driven The machine
must be capable of straining the ap-
piled pressure after the unsetting is
, completed.
: Field riveting must be reduced to a
, minimum or entirely avoided where
possible.
The effective diameter of a driven
; rivet will be assumed the same as its
diameter before driving. In deduct
ing the rivet holes to obtain the net
sections in tension members, the dia-
/ meter of the rivet holes will be as
J sumed as one-eighth (B) larger than
the undriven rivets.
For main members and their con-
nections, no material shall be used oil
: less thickness than Il of an inch
5 and for laterials and their connec.
lions, no material less than 3-16 of al
: inch in thickness; except for lining
f or filling vacant spaces.
The pitch of rivets at the ends o.
compression members shall not ex
: coed four diameters of the rivets fol
: length equal to twice the width O.
$ that member
The open sides of all compression
5 members shall be stayed by batter
Y plates at the ends and diagonal lat
: tice work at intermediate points.
All bed-plates must be of such di
mentions that the greatest pressur,
: upon the pedestal stone shall not ex
> |
. EXPANSION. Proper provisions
: shall be made for expansion and con
: traction of steel spans, by providin,
roller ends where the span length ex
2 ceeds so feet. Spans 60 feet or les
2 shall be firmly anchored to the abut
ment at one end and left free to NOV,
longitudinally at the other on smootl
plates, and anchored against lifting O
/ side notion
All-rollers shall be friction roller
I running between planed surfaces
These rollers shall not be less than
; inches diameter.
ERECTION OF SPAN. The contrac
tor shall furnish all staging and falls
work. Shall erect and adjudge al
metal work and complete the spans
! together with floor systems and rail
! ready for travel. He shall anchor tn,
spans with proper anchor bolts to tn,
concrete. He shall use such falls,