New-York tribune., 1908-05-19
STILLMUM OVER BRIDGE
MCZZLE ON ENGINEERS.
Mr.. Stevenson Won't 4llosC His
assistants TO Discuss Test.

II
s.tu no answer is forthcoming from the engineer
ing staff of the Bridge Department TO the array Of
facts already published in The Tribune. which go
70 show that there is grave danger OF the Black
ueIs TsIans Bridge oolapsing IL IL is loaded the
Bridge Department purposes to load it
T-,,.siaresv after the publication of the story
r.. tribune On Tuesday last. the Bridge Commits
sso,e- was sure his Erourd- He promptly char
..,.-ize5 the story absurd Chief Engineer In
se-soll and his assistants expressed the opin
ion Mayor Mcclellan facetiously remarked that
n. expected an invitation the collapse when
Il did place
AT the conference between the engineers of the
Bridge Department and the newspaper men on
Wednesday morning last, John B. wilkins, the
member Of the engineering staff personal charge
Of the work Of construction upon the bridge, stated
that the highest calculated stress purposed TO be
put upon the main compression members was 1900
pounds TO the square inch This statement was
concurred in by Chief Engineer Ingersoll
Commenting upon this assertion Gustave Linden
thai. former Bridge Commissioner. who designed
the original bridge stated the most positive
that there was grave danger of the structure
collapsng Il the main compression members were
subjected TO a stress OF ao pounds 10 the square
inch
Chief Engineer Incersoli. when asked how il was
that the Blackwells Island Bridge was considered
safe with its main compression members under a
stress Of 2o9o pounds to the square inch when the
Quebec Bridge fell when its main compression mem
hers were under stress OF only 1900 pounds 10
the square inch. replied that everything depended
rpor the design Of the main compression members
Those members OF the Blackwelfs Island structure
he said were $ designed that they would be able
:, u5+bs-and the stress of 5000 pounds TO the
square inch and more
COMPRESSION MEMBERS WEAKER.
r- I.ndenthal on the other hand. gave If as his
crinion that the design Of the main compression
members the Blackwefs Island Brioge as erect
.d was inferior the design of the corresponding
sre5s str
T--,on the same day that Commissioner Stevenson
issued his mandate that no employe OF the Bridge
Tlenartrnen- was discuss the question OF the
safety Of The BlackweI-s Island Bridge he issued
2 short statement, upon which, he said the de-
rartrnent would rest its case This statement was
10 the effect after the collapse OF the oueOec
bridge Chief Engineer 1ngersoh, accompanied ps
Henry Is Seaman. John B. wilkins and Leon ..
Neoise.i engineers of his staff had been Instructed
70 20 TO Quebec and examine the fallen bflose-
Aer their return the computations for the Black
wells Island structure had been all rehgured
The weakness which existed in the quebec orldse
did not exist in the BlackwelIs Island Bridge The
engineers who TO Quebec and had afterWard
made The denomination Of the local structure
had reported verbally to MN that tIe Ui4uso was
absolutely safe.
This statement promptly denied by Henry d
Seaman. now chief engineer Of the Pubic service
Commission one Of the engineers who the CON-
missioner said made the REORGANIZATION More Ilah
-hs- Nj Seaman expressed the conviction that the
engineering staff Of the Bridge Department would
,-eOor7a any investigation demonstrate "he1ht
ne bridge was safe not. The other engineers
- -,sse tho Examination are still in the en-
rIav II the Bridge DepaTtmnt and their NOUNS
So closed by the Commissioners orders that the
matter must not be discussed by any OF his en-
Ployes-
COMMENT OF ENGINEERING NEWS
With respect 10 the statement made by Commits
s5oner Stevenson that The engineers of his Depart
-ren- aho went 10 Quebec found out that the weak
ress which existed in that structure did not ehisl
:, The B!ackveITs Island Bridge. q comment maze
in The Engineering News" OF April . OF TINS year
,, the failure OF the Quebec bridge is interesting
sn.ciallz noteworthy is the fact that, while chord
: l zone Of the lower chords was oeloTl!leu I
15Sr ~ s chords sere aiready buckled in such way
that their failure at @ ssRs 2s1I of the bridge is not
attributable chance unfortunate osL0ri m M ~
q single chord: At least three chords al [MO
widely separated points, had reached a Coiearei e
OF immediate danger. and Two OF f1s men ori bV
the fact that chord A L had got aheao OF 'ieNi
in reformation
i is pointed out by engineers that this comment
,,,n re reror- Of the commission that investf-
gated the collapse Of the Quebec bridge indicates
resrl, that il was not weakness in any inolFlduaI
main compression member Of the bridge 1hat
caused il 20 fall There was more or less seile
failure Of the main compression members. "hlch
indicates that the structure was oFerioaoeu D
-qrd rf,e capability Of those members TO with
end the stress put upon them. The PLAIN 1ac''
.. = aser-ted is that serious error was mace IL
,or7-utinr the strains, and this fact is commented
,,pon n the same periodical as follows:
The fart is that J. Stirling Deans, chief engn,eer
- re pbcrrfK Bridge Company Z l. ozIaP5e
$50 Designing engineer Of the FhoP1llN t'L.ct
.----,z-y and Theodore Cooper, consuI'Ils ing
- -err7f+teG the shops emo rolhhs Hl4I.S -
l.cs, sro-L. without taking any steps 70 tes ~.
-o--eo,ress Of the assumed dead loao, aIu . olL-
--o57sr1e lead load not appear 70 aNe
t.s-~.-s7 from the nlans until AZ least elShtet-i
, -ar he work OF fabrication was begun
pprr,cr- PLANS CHANGED RECENTLY
The mans for the Blackwells Island Bridge haNe
.esr cor,nletelv changed since the contract 10Y
-,e erection OF the superstructu7e was a"diHe-'
-le engineers OF the Bridge Department aIii
49, -re-e has been increase in the oeau 'ost
n y -e- cent over the dead load assumed III 'i1e
,-fgfraI r1a-s but il does not appear 1la' any
.-4-e have been taken by the engineers OF t.4s
-,5z. T1ersrtr7e-t 10 test the correctness CT 'le
-ru- assumed dead load. CHIEF Engineer lHs"i
.or ..,-s -rs- the new strain sheets we're eo' o1N
-a+o-e : mound Of steel Ras rolled Tor the prlos
Wen asked 70 produce those ne" strain shee1s 4i7
.vh.hi-ed 2 set Of blue prints. stamped as re-
,.,,,5 = -be r)enartrnent Of Bridges on March ID
-. ~ that tine more than ten thoosahd tOiIs
q. -he sr-erstr11cture had been fabr1ca'ed III 'ie
s-c-s From this il would appear that not oillS
-e-e ~ -esrs made OF the new assumed oeao Io@1s'
f,r- rhe new strain sheets themselves co ho1 0P
-ea- p have been prepared by the engineers oI
--e 5e7ar- --er- al all inasnuch as they were oliS
gee 6 il, the department many months altef 'iie
<ss-icsrjng bridge members was Ues I'LL