The Athena press. [volume] (Athena, Umatilla County, Or.) 18??-1942, 1911-12-29
NATURAL BRIDGES
We Can Boast Of at Least Nine
of Them In This Country.
OUR FIRST WOODEN BRIDGES.

They Were Built About 1900 In the
Eastern and Central States, and Then
Came the Covered structures-Few
Iron Bridges Prior to 1850.
Nature has provided this country
with at least nine natural bridges, one
In Virginia with span of about nine
ty-three feet and about 200 feet high;
one in Alabama with span of about
seventy feet and about 1870 feet high;
Eve In California, the largest of which
has a span of about eighty feet and is
about twenty feet high; one in Ken,
lucky with a span of about seventy
feet and about 1870 feet high, and one
in southern Florida of somewhat
smaller dimensions.
Bridge building in the United States
is Of comparatively recent accomplish.
ment. The early settlers were com
PEELED to ford the streams or cross
them on RATS or in dugouts. When
Washington crossed the Delaware with
his army there were no bridges over
that river, and history records many
Instances Of streams being forded with
untold hardship and the consequent
disasters and delays. Such incidents
become serious matters when, for ex-
ample, physicians are unable to reach
the sick or injured because Of impass-
able fords or are compelled to expose
themselves to unnecessary danger
Traffic conditions in general are de-
moralized by unsafe bridges or cul-
verts.
Pontoon bridges have served tempo
rary need in many instances, but espe-
cially in warfare Mention Is made of
their use very early in history, and one
Of the most notable occasions was
when the Persian army under Xerxes
crossed the Hellespont on two pontoon
bridges consisting, one of 360 vessels
and the other of 314. These were an
chored head and stern alongside of
each other, with their keels in the d.
rection of the current
The Romans had wickerwork vessels
covered with hides destined to support
the timber platform of bridge. These
formed part Of the train Of their ar
mics throughout the history Of the en-
pire until 476 A. d.
The construction of highway bridges
In this country began to assume prac-
tical proportions about the year 1900,
when many wooden bridges were built
In the eastern and central states by
Theodore Burr and Timothy Palmer.
The wooden lattice truss was intro.
duced about 1920 by Ithiel Towne.
/ Many Of these bridges, consisting Of
planks pinned together in lattice work,
were built from this time on, and they
became well known as "T0wne" or
covered" bridges. 1t is doubtful il
much attention was given to econom-
ieal design. An effort was made to
protect the trusses from the weather
by wooden roofs and sides in some in
stances, but very few were ever paint
ed to preserve the timber. This early
type of bridge did service for many
years, and some are still in existence
In Indiana and elsewhere
The first covered bridge to be built
In Tippecanoe county and one Of the
first in central Indiana was the
Brown street bridge over the Wabash
river at Lafayette, according 10 the
records on file in the office Of public
roads, department Of agriculture. This
old structure, that had been condemn
ed for good many years, has long
since disappeared. However, num-
Der of covered wooden bridges that
were built more than half century
ago are still being used within ra.
dius of fifty miles of indianapolis.
Few iron bridges were built in this
country prior to 1850, and it was only
in 1S47 that the first publication in the
United States, discussing the rational
design of bridge members, was issued
by Squire Whipple of Utica, N. Y.
Wrought iron began to replace cast
iron about 1868, but steel was not used
until about ten years later. The adj
vantage of steel over cast or wrought
iron lies in its greater tensile strength.
Foremost among structures repre-
senting some of the attractive as well
as substantial features in good bridge
designing of the present age may be
mentioned the Washington bridge over
the Harlem river III New York." said
the superintendent Of construction OF
bridge engineering. Office OF public
roads. Washington. -