The daily morning Astorian. [volume] (Astoria, Oregon) 1883-1899, 1896-05-13
THE OLD BRIDGE.


Niagara BuspenAlon Bridge 10 he Ito
placed
| The old railroad suspension bfldg,
across tho gorge below NlaRarn Fails II
10 bo replaced by steel arch. This hn,
boon under consideration for good Will,
ana Mr.. h. l.. Buck. chief engineer foi
the bridge companies, prepared plans and
estimates Of cost some months nRO Re.
Gently an agreement was entHr9d into be-.
tween tho Niagara Falls international
Bridge Company ana 'he Niagara Falli
Suspension Bridge Company on me side.
rho owners Of the bridge. ana th1 Grand
Trunk Railway Company on the other
aide. ha the actual users Of lhe bridge,
under which work can b. hogun at once
In building the now structure, Plans
and specifications hays beon rent out for
bids, ana II In believed that work will be
begun this summer.
The existing suspension bridge was
completed In 1855, II was built from the
designs Of Mr. John a. RoebllnK. ana
under his supervision an chief engineer.
II WAS very remarkable engineering
work In its day. and has stood ~ mon
umcnt 10 the genius Of iA designer. 10
isso tho suspended structure and In ihSs
the towers were renewed. from the de-
signs OF Mr. l.. l.. Buck, and under his
supervision. This work was lone with
out intorruptinE trnfiic. and In considered
10 haye been one Of the most daring and
original things over attempted hy an
American engineer. Boon the record OF
this important work Of Mr Hoobilng and
Mr. luck will exist only on paper.
Iiids are called for tho construction hnd
erection Of the metallic HuperAtructiiro
ana for tho removal OF the present rus-
pension bridge and towers, The masonry
foundations and the temporary anchor
pits will be prepared by the bridge com
phny
Ilhr bridge will have a main span G1
feet long between ccntorH and end pins,
and will bo connected with thr top or
the blum on each side OF tho river by q
truHued span rs feet long The main span
will be AN arch with horiEenlb upper
chSrda. hinged nt the sk, NbackH. ana
each tfuns will have "a batter Of one
horizontal TO 10 vertical The width be-
tween the axes Of the top chord viii be-
~ feet. between tho hycu OF the rib at
the crown it will be- ~ feet. and between
cuntrrH of akrwbackH II will be- ~ feet
~, inches. The aseH Of the upp n chords
viii b. i5l feet above the skcwbackH cou-
trrr. and the axes ~ tho ribs az the
crown vii b- iii feet above tho skew
backs one end OF each shore span VIII
bs hinged TO the arch by pin at the
intersection OF the ond post and top
chord OF the arch and the shore end viii
rest on expansion rollers IN masonry
ahuimenu. The bed plates OF the arch
will rest on masonry founded on the
rock
The bridge has two floors. the upper
one carrying the railroad tracks and the
lower one the highway. sidewalks ana
trolley track
over each post. rrsihK on tho upper
chords OF the arch will be transverse
steel beams Between these beams. fiy-
ctrd 20 tho wells. will be- four lines OF
longitudinal Htringeru. feet apart. d.
rcctly under tho railroad tracks. The
ends Of the transverse beams and the
railroad ties will bc covered by a ,tcel
plate extending from end 10 end OF thr
bridge and from the top OF the upper
chords 10 the tops OF the Ties. She hand
rails OF tho railroad floor will be secured
to angles along tho top edges OF these
plates.
The lower noor will consist OF trans
verse beams and four lines OF lonKitu udin-
al steel utrinKuru about II feet apart. Tho
two interior lines OF strinEers will be
rivctcd TO the webs Of the beams. The
outer lines will be In the planes OF the
truHseA and their ends will Do riVeied 20
the posts. Lying across tho Strlngers
will be i.beamr, which will extend feet
outside OF tho truKsos on each side 10
carry the HiicwalkH
The lateral braclnE between the top
chords will be stiti diAgonala formed with
angles rivctcd to the chords and to their
Intersections with the lower llanEcs or
the steel Htringcrs These Sili form
continuous system OF bracinE from short
TO shore. ERch bent OF the arch span
will have web plate secured to each
post and taporcd to make the inner edge
vertical The vertical edges Of these
plates will bc Hanged. with angles rlVeted
to them. and there will Dc knee braces
from these fAnges to the lower flanges
OF the transverse beams OF the upper
floor. Tho web plates and their nauges
viii be riyctcd 20 these transverse beams
Each bent OF tho arch below the lower
floor will have a system OF sway braclng.
OF steel struts and iron rods
extending TO the arch ribs, The lateral
bracing OF the ribs will be entirely Of
angle struts and lattice,
Tho crosstics OF the railroad track will
be 10 inches by 10 inches by 10 feet. laid
ii-lnch ccntcrS. resting on the longitudn-
NJ stringcrs, Immediately over the string
crs. resting on the ties will be guard
llmbcrs inches by inches. notchtd
one inch over each tie. and secured by a
scvcn-clghth inch bolt 1t sach third tie.
passing down through the guard timber
and tie and the upper Aange OF the
stringcr Every fourth crosstle will be
extended TO carry tho Slats for walk
outside OF each track. and similar walk
win be placed between the tracks Gal
vnniEed iron troughs viii be placed be-
tween the ties TO drain the water toward
the optsldc. where II will be received by
proper conductors
The highway floor will be laid on Joists
I inches by 10 inches, and he whole car
ana trolley track to the width
OF e feet will be planked with three-lnch
oak plang laid lcngthwise on the bridge.
ontsidc this viii be sidewalks laid in
two-lnCh white pine plank, Thes viii be
about six inches above the carriageway.
The short approach to the ii5-foot span
at either end will be Of plate girder spans
the floor system being similar to that OF