The daily dispatch. [volume] (Richmond [Va.]) 1850-1884, 1877-05-26

ANOTHER RICHMOND lNVENTION-TUBULAE
BRcH.BR1DGE WITHOUT .TENsI0N-RoDs OF
AoLTs.-M John II. Snyder, OF this city,
who is already well known to the public In
connection with his horseshoe machine,
cotton-compress, and other valuable inyen-
tions, has Just obtained patent for an iron
bridge combining strength, economy, and
beauty in construction.
The model represents tubular arch
bridge without tension-rod5 or bolts. The
span OF the bridge Is 800 feet long, drawn
to scale Of one eighth OF an inch to the
foot, consequently this model is 31t inches
from pier to pier. The model is made oil
light tin, and weighs less than three pounds.
Tested in the presence OF number OF citi--
zens, it sustained weight OF 500 pounds OF
pig-iron, applied in the centre OF the span,
without showing any signs OF weakness or
straining any part OF it.
The inventor is confident that no other
truss-bridge of any construction now known
to the art OF equal weight OF material and
representing as long span would sustain
as great weight. He claims, too, that it
is cheaper in its construction than any other
iron railroad bridge Of equal span. In CIV
ing the weight and dimensions Of q full-size
span OF 800 feet he describes the size OF the
tubucs and weight OF material in the tubes,
and its peculiar construction, as follows
The two horizontal tubes running from pier
to pier are constructed from boiler-plate one
fourth OF an inch thick, four feet high, and
two feet wide, the corners to be three-inch
angle iron by fve-sixteenths thick, to which
the boiler-plates are rivetted on each corner.
The weight of such tube would be 100
pounds to the foot.
bo orob i, ooncf71Jafo6 fha coma the
tubes, with depth of five feet instead OF
four, resting upon projection of the pier
twenty-four feet below the tube, and con-
uecting with the tube forty feet from the
pier, continuing the true circle OF the arch
from the upper side Of the tube to the
crown or centre Of the bridge, thirty-two
feet above the track. The horizontal tube
answers double purpose: as tension-rod
to support the arch, and base for the track,
thus preventing any side-pressure against
the piers. The arch and horizontal tubes
are united by the use Of rolled iron bars,
six inches by three.eighths OF an inch, placed
about four feet apart, made in the shape OF
a staple, dropping over the top OF the arch,
and rivetted to the arch and the sides OF the
horizontal tubes.
The weight of the arch would be ITO
pounds to the foot. The ties consist OF
beam iron rivetted to the. upper side Of the
horizontal tubes about three feet apart,
upon which the track is rivetted. AS the
bridge is wholly constructed OF iron, the
expansion and contraction Of all It's parts
will be equal. On the under-side OF the
tubes braces are rivetted, making the bridge
very strong laterally. The weight OF such a
bridge would be GAO pounds to, the running
foot, independent OF the cross-ties and
braces. TO show how desirable this is to
bridge-buiders, the inventor states that
there are no patterns needed, and no forg-
ing, or bolts, or screws used in its construc-
tion, but simply bar-iron and boiler-plate
rivetted together. Consequently, he says,
this is frmer and safer than any other
bridge now in use. The principle OF this
bridge has been examined by competent en-
ginecrs in New York city and pronounced
the strongest form OF truss-bridge.