The sun. [volume] (New York [N.Y.]) 1833-1916, 1879-02-18
INVESTIGATING THE BRIDGE
TEsTIFTING TO ESTIMATES As TO ITS
STRENGTH AND SAFETY.
Explaining lite Construction aud the Means
Taken to Insure Both-BulIt 60 sustain
Five Times More Than Can he Put Upon IL.

Ehte lue cnuTRes muue ughlnSt tne BfOOklyn
Bridge by its opponents that 1t will impede the
free and common navigation OF the East River;
bo serious obstruction to the commerce OF
New York. and to the growth and prosperity of
the port: will not adequately provide certain
and safe mode Of travel bctwecn tho two cities;
will not be of any substantial benefit to either.
while IL will reduce largely the value of property
on the East River In both cities; and that 1t
will he an insecure structure, on account OK its
great length. and cannot bo properly stayed and
protected at its great height against strong
winds. Tho Committee hal given motto, that
they would take testimony In regard only
to the bridge being an obstruction and TO is
being insecupe. and Mr. Henry G.. Murphy. rs
the President OF the Board Of Bridge Trustees
came prepared 10 prove b. competent wit
nesses that these allegations could not be sus-
tanned. First however. he said that he desired
to DO recalled in order that he might correct
and modify certain points In his testimony Of
Saturday. IIo thon submitted TO tho Commit
tee list o. the different payments Of
| tho shareholders In tho old Brooklyn
Bridge Company. as he had rromised
20 DO and he also laid before them O COPY oi the
first estimate oi the cost = the bridge made by
| John A. Rooblng in 1851 In tLis estimate
which was for n bridge a'tsr the same plan. but
not as good as tho present structure MIR. Roeb-
ling said that he thought that the bridge would
not cost more than $4,000 900 or s7.0OOO0O
Then Mr.. Murphy explained that, in estimating
| that the bridge could be finished for SO 100000
he did not include the motive power AMI ap-
| parntus for propplling the cars ThM would
cost 500 900 or i70 .UO0 more. Also In regard To
| the revenues accrulng from renting the prop
erty under the approaches - the bridge. He
thought that they would amount TO 100000 an
nunlY.
Mr. Philip b. Low was the next witness There
was no Bible in the comm ttce room. and none
seemed prorurable, consequently Mr. Low nf-
! nrmed with uplitted hand that he would tell the
amodel OF a ship completely rugged. This WAS
! about four feet long. and was placed in the
middle Of the Committees table. Mr.. Low said
| that he was snip rigger by trade, ana mad had
thirteen years experience In It, He had made
| measurements Of ships masts and estimates
| from drafts. and according TO these. in his
| opinion all ships not exceeding SIS tons bur
| den. with possibly here and there an exception.
could pass light and unnden under the bridge
at any point where II was 1874 feet above the
river at hall tide. Mr.. Lows further testi-
mony was that in his opinion. with the ex-
| that always discharge In the North River. and
| the large pleasure yachts, there were no harks.
the Matilda Cranz and the Frederick. that could
not readily pass under the bridge at hall tide.
and very few which could not do 40 ut full tide {;
and he thought that there were not more than
year which would require the housing OF
topmasts. Then the witness explained how
topgallantmasts were housed. using the model
| 70 illustrate and said that the cost OF housing
and sending them up again complete for sea.
| by riggers independent Of tho crews. would run
from $50 to $50. depending upon the size Of
the yesscl and the state Of ths weather;
Col William II. Pane testified that he is tho
Assistant Engineer of the Bridge. and has been
since 1869, For a quarter Of century he has
been civil engineer. lie was frst employed
on the caissons then In the construction of the
New York tower. then in tests and experiments
| terials used and lgtterly In superint nding the
laying Of the cables. and in max ing calculations
in regard g the suspension Of the super
structure. He then explained how the cais-
casson had been carried rs fret below
the water was about twenty-five feet deep At
| the depth OF ~ feet they reached bed rock. The
| weight OF the New York tower masonry was
90 900 tons. The pressure at the bottom Of tie
cRsson, on the bed rock, was four and a half
tons to the square foot; at the base Of the stone
| work eight tons. and at the base Of the centre
| column. between the roadways. and on level
with them. the pressure was twenty nine and
| half tons 10 the square foot That was the
greatest weight stone OF II similar character
| to that OF which the tower WAS built had stood
| " But what Chairman Knowles asked. will
| be the effect Of time, moisture, and the like
upon the wood work on which the towers
Col. Paine. replied that It was we'll known to
engineers that at a depth below the surface of
| the earth where there were no changes % tenn
pernture or conditions. as Of moisture. dryness.
| and the like. wood was almost indestructbe.
| Piers OF bridges, built 1000 years ago had been
| Chairman Knowles wanted 10 know whore
that bridge was The witness said 1t was in
bers had been found loo feet below the surface
| that must have been buried for centuries and
| yet they were perfectly sound. History told OF
submerged forests
The settling OF the towers was the next ques-
| tion TO which the attention Of Col. Paine was
| called. He said that IN building the calsson of
| the New York tower number OF timhrrs had
| been bolted together. In this operation there
was "A gHin OF "a Inches, the umb'rs not
canning together. He mad nee ted flgf the
| tower would settle nj least that much. Careful
observatonsilad been made. Az the ston" work
arose above the water. spikes were put IN the
| masonry and careful levels taken. The result
WAS that the tower had settled only one inch
| poded. This settling had been very evenly
| dlstr buted over the whole surfac" Of the tOwer.
what are the elements OF the strength Of the
! bridge ~ the Chairman asked
| Col. Paine replied 10y giving brief descrp-
ton OF the towers. hnchor4ges. and cables. The
| HnchoraRes served 70 hold the cables. There
We're first four large bed pGtrs of iron. Tothrse
| were secured chains, The cables Wore attached
| to these chnns. There were 10000 tons of
masonry IN euch snonoras, aud Of the GO.OuO.
there were G.O39 tons over cngh bed plato. The
strain ON eacn plate would be / i.7b' tons The
every particular there had been IN cf-
iofrt 10 make every part Of the
the Original plan II Mr.. Roebllug IN, strength
Oi the cables wts l2OOD tons vhch Tho attss
would pnss from Oh" towers duWn. hnG b. So
cured 10 the ttussos : at various distances. They
controlled Tho weight 80 mat the .bfliso would
not act That is. one part sink Rud another
rise. No part OF the hridLo could suF without
Il cores spOndln2 elevation in another part. The
stays prevented this. They sustained a strain
Of 1852 ions each. on each side of
the bridge. They were the great ica,ur.
Of Dir HoeblpR plan, and made the birds,
superior to all others. which were mair on,y
with suspcLdeIs. These stays prevented ne
wind uuler the bridge from lifting IT, They
also prevented swinging. lol they were on IN
any lc. bang nine feet further IN Al tnt badge
thau al the towers. They ouANrr,ed. Tho force
ol tao wind would bring an the says and two
cables To- resist IT, There WIS 1lS1 "A system %.
heavy stays running irum the lowers 10 ti.n op-
poslte SIDE o. thc lr!Lso. THIS Nus an inn
provemcut on ~" Niagara triI.ge. where ,Ae
storm stays Ware attached to distant objects
There thoY worked against eueh other. AID
were more affected by hrHt nl cold.
Bong asked tD Siye Tho strength Of the bridge
ir detail. Col Paine SAID thai WHEN the bridge
was nNed with ears. teams. and piesrul,rrs
tnere would b." distributed strain Of 50 pounds
per square, iuut The bridge WIS able to stand
u strlln of o9-lOO tons 10 me llneal foot II had
been calculated that 72OO teams could pHss i'm
al hour. ~ the rate of 700 feet IN minute: so
ears could bo allowed ON the bridge ut once,
allowing six minutes for crossing: cayh car
would hold 100 passengers. Thus 50 900 phs-
sengers could cross IN an hour. besides those
on foot The strain On tho anchorage WAS
about four times less than tho margin of
safety; that on the suspenders clght times lrss.
Tine SutB distributed load Of the bridge WIS