The sun. [volume] (New York [N.Y.]) 1833-1916, 1915-07-15
OUR BRIDGES ARE SAFE.
Wood Pavements Are Not . Source
Of Danger In New York.

Of Danger In New York.
To II EDITOR OF THE SuN-Str. In
a letter to you referring to the burning
OF tho floor OF Belle Isle Bridge. which
caused the collapse OF that structure,
Walter 4. Kruesi says that my plan to
pave Brooklyn Bridge with wood blocks
seems a hazard which shout be avoided.
Your correspondent admits some uncer-
tainty as to this hazard in the following
query. ! quote: IF a fire were started
BY an automobile, q trolley car or other
wise. freboats would be useless. would
they not?'
The Brooklyn Bridge has had a wood
pavement since 1t vas opened, more
thar thirty years ago. II is now paved
with untreated spruce planks laid upon
treated pine planks, which are fastened
t. an open steel floor. For thirty years
II has carried locomotive drawn or cable
hauled or electric driven trains Of pas
senger oars; for seventeen years 1t has
carried surface electric cars on the
roadways; motored vehicles under GER
tain weight and speed restrictions freely
use tho bridge. As a result OF these
conditions no considerable fire has ever
occurred here.
My plan is to lay treated pine blocks
upon untreattd pine planks in place OF
the present pavement. BY simply bring
Ing the wear upon the end OF the grain
OF the wood blocks. instead OF upon the
side OF the grain OF wood plankS | will
rid the bridge OF its present splintering
pavement and give II a smooth one.
Any combustible material entering
Into the construction of a long span
bridge would be extremely objectiona bic
and hazardous OF fire in the absence OF
suitable fire prevention measures. The
passage over the bridge OF vehicles
which nigh set fire to themselves or
TO the bridge would also he Objectionable
Tor the same reasons. A suitable fire
protection system Is maintained on each
OF the city's great bridges ain all
such accidents. This system includes
a regular patrol inspection. means OF
communicating a fire alarm, auxiliary
hre hghting apparatus and stand pipes
BY which the city's fire department may
deliver water at high pressure to any
part of the bridge deck.
The new pavement will introduce no
hazard greater than that which has
proved to be entirely safe in connection
with the other suspension bridges over
the East River maintained by this de-
partment. The Manhattan Bridge, next
upstream from the Brooklyn Bridge, has
a treated wood block pavement laid upon
a treated plank undertook. The Will
iamsburg Bridge, next upstream. has a
treated wood block pavement laid upon
a slightly pen stesl underdeck. The
greensboro cantilever bridge has a
treated wood block pavement laid upon
a concrete foundation over "A closed
steel undertook. rhese bridges, sever
ally, have had no other aveme since
they were opened to use they are car
rying a great variety OF trafic. day and
night. which totals upward OF zoo. 900
tons for twsnty-four hours. Due TO the
effective ness OF the fire prevention
measures taken by this department in
connection with them. every Are that
has occurred on them has b en- prompt
extinEuished
During the construction OF the Man
haitian Bridge the treated timber deck
.ns on the westerly side of the Brooklyn
end span took fire, which "a strong wind
carried the length of the span. This
fire threatened the destruction OF the
bridge. but Was successfully fought by
the city's fire department without the
aid OF any FIRE protection system such as
now forms Il part of the equipment of
that bridge.
In the absence OF a better material for
paving long span BRIDGES wood must be
used. Fol the wearing surface OF the
iosdways wood Is lighter than any
other paving material. For the under
deck wood possesses the advantages OF
lightness and iieNibility 10 "a greater de-
gree than any other material TN long
spans the weight OF the matt rails used
Is an element OF the highest Importance,
and where these spans approach the
gNatest length possible for the type Of
bridge in which they are built, 10 take
care Of the moving loads which will
come to the bridge. II is absolutely nee
fssary that the dead weight OF the
bridge be as small as possible consistent
with the necessary rigidity Of the struc-
ture. The timber deck results from
these conditions. Its use, however, ne
cessitates the precautions against fire
such as already ave been taken by this
department. The mere substitution OF
blocks for planks or OF pine for spruce,
or the inversion of the position OF the
treated and untreated wood in the pro.
posed new pavement of the Brouklyn
Bridge, constitutes no especial hazard
Experience has shown that oply surface
burns. which do not spread. occur 10
wood blocks when they are confined in
"a pavement.
The nre department having demon
strated Its ability to reach the deck OF
an East River bridge with a stream
from its freboats. and stand pipes. hav-
Ing been provided for the connection of
both the land and the water apparatus
o. that department. SO that any hre MAY
be fought from the top as well as from
beneath the bridge. these considerations
together with the presence on the bridges
AZ all times of available forces Of men
and OF portable fire apparatus. of sand
and OF water in tanks which are KEEP,
ready for use. make II apparent that the
hazard which your correspondent appre.
hends has been Iet in every reason
able way by this department.
r. j. II, KRAcRE,
Commissioner. Department OF Bridges
New YORK. July IA.