The Ely miner. [volume] (Ely, Minn.) 1895-1986, 1935-04-26

Nv vi To be strictly accurate one should
say "the two greatest bridges in
" the world" for there two prof.
ects under way at the same time in
the San Francisco bay region and each has GER
tain characteristics which make them pre-emi-
nent among such man-made structures. 1t all
depends upon what one means by greatest"
If by greatest" you mean largest" and "long-
est" then it's the San Francisco-Oakand Bay
bridge you'll be talking about. 1t will be eight
and one-fourth miles long, almost three times as
long as the present worlds largest and longest
bridge, that over the Firth of Forth in Scotland.
If by greatest" you mean the longest suspen-
sion bridge" and the highest bridge" then
you'll be talking about the Golden Gate bridge,
the 4200-foot length of whose main span makes
1t the worlds outstanding suspension bridge and
whose 750-foot towers make them the highest and
largest bridge towers erected, $50 feet high
er than those of the George Washington bridge
across the Hudson river.
In either case it is impossible to talk about
these bridges without dealing in superlatiyes,
for each has in one way or another exceeded all
previous records as to size and, taken together,
the two projects establish a record which prob
ably will not be exceeded for centuries. They
are man-made marvels on a scale so colossal
as almost to defy description. The statistics
alone are imposing enough but to make them
understandable to anyone who is not an engineer
II
as these:
In building the San Francisco Oakland Bay
bridge they are using 100000 board feet of
lumber. Do you know how much that is? Well,
it's enough to build 5000 five-room houses or all
the houses in a town of $4,000 people.
Have you ever seen the city hall in Los An
geles, or the Russ building in San Francisco or
the L. G. Smith building in Seattle? The con-
crete and steel in this bridge would make So
suph hu nft thrpa
1t would probably be difficult for you to WIS.,
ualize 1880 tons of cable wires. But If you're
told that the cable wire used in the bridge Is
long enough, if laid end to end, to encrcle the
earth nearly three times you'll get some idea Of
how much wire is going into that bridge. And
the cable wire is only small part of the metal
that's being used The structural steel, reinforc-
ing steel and cable wire necessary for the bridge
will take 81 per cent of the entire steel output
of the United States in the year 1888.
You've seen 60-story skyscrapers? Well, each
individual tower of the bridge, standing more
than 700 feet high from the base of it's pier on
the floor of the bay to its tip represents con-
struction job the equivalent of such a sky
scraper.
So much for the San Francisco-Oaklan Bay
bridge Now for some comparative figures on
the colossus which will span the famous Golden
Gate through which rushed the gold-mad argo-
nauts of 1S49.
It's not nearly so long as the other one but
because it's the worlds largest suspension bridge,
they had to do a lot of digging and building to
support the tremendous weight of it's 4,2O0-foot
CHATS more than three-quarters of a mile, you
know y span.
Imagine tunnel 10 feet HIGH 10 feet wide
and 26 miles long. That was the total excava-
ton for the Golden Gate bridge
If all the cement that will be used in 1t were
to be delivered in barrels in the old-fashioned
way and these barrels were stacked one on top
of another, they would make a pile no miles
high Or, to put it another way, If all this con-
crete were used to lay sidewalk you and two
of your friends could walk abreast on that side
walk all the way from San Francisco to New
York, for it would be five feet wide and 3,1S6
miles long.
You've been on top of 22-story bulding2
Remember how small the people looked on the
street down below? If you drive your automobile
across the Golden Gate bridge In 1887 and look
down at the people in the boat passing under
the bridge they'll look just as small.
And speaking of automobiles-over the six
lane roadway of the bridge there could pass a
string of automobiles reaching from the Oregon
line to the Mexican border and moving at the
rate of % miles an hour. Sounds like a good
place for Sunday afternoon drive if you want
TO avoid traffic congestion, doesn't IT'D
And no matter how many automobiles were
on the bridge at one time there's not much
danger of the two cables which support 1t break
ing and letting you drop down into the water
below You see, each one is 3615 inches in diam
eter and weighs II, 500 TONS There 27,572
separate wires in each and If all the wires
were laid end to end they would reach $4,000
miles-wen three times around the world.
Yes the Golden Gate bridge is LARGE and so
Is the San Francisco-Oakland Bay bridge In
fact the latter is composed of two enormous
structures each longer than New York city's
pride the George Washington bridge across the
Hudson. 1t is a combination suspension bridge
between Rincon hill in San Francisco and Yerba
Buena island out in the middle of the bay and
a cantiever bridge between the island and Oak
land Yerba Buena island will be crossed through
the largest vehicular tunnel in the world, the
bore being rs feet wide and IS feet high
The Bay bridge proper, including the island
crossing, will be approximately four and
half miles long but its total length from the
end of the western approach to the end of the
eastern approach will be eight and one-fourth
miles long. The bridge will be double-deck
structure with six lanes Of automobile traffic on
the upper deck and three lanes of trucks, plus
two interurban tracks on the lower deck.