Richmond enquirer. [volume] (Richmond, Va.) 1815-1867, 1833-05-14
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ARBAsuRY DEpARrAfrNr
,TVHE Pre.idsn. Of tho United State, i. hsy ioSS, a..Ia.a
Il on the plan Of the Bridge authorized 10 be- built
Proposals, sealed and endorsed, will be received bv shs
secretary oil the Treasury until tho 10Th of Nav. incIu-
sive' ior the materials and workmanship Of the same, agree
ABLY 70 the terms and specifications OF the work.
The Bridge will have al arches and draws. AZ oier.
ana 2 aoutments with their half piers. The arches to be
10 leet span and 20 feet rise above the springing line, and
10 DO curves oil several centers, or semi. eipscs. The ri.
es and abutments TO rise Z feet above low water. and to he
OF sufficient breadth to sustain each the force of its depen.
dent arch.
The draws to be each 65 feet wide;-one to be p,a.sa
at the Maryland, or Washington channel, the other at the
Virginia channel. The bridge to be SO feet wide between
me parapets, and the carriage and foot ways to be horizon-
tai from abutment to abutment. The piers, arches and
aoutments to DO Of granite, and to be founded on piles. Or
on the solid rock, according to the nature OF the bottom.
The parapets to be each Is inches thick and 4 fe.t h;oh
above the roadway. The arches to BIO 3 feet 6 inchs.
thick at the Key. and 4 feet 8 inches at the springing line;
except the facing or ring stones, the extrados of which
will be a segment of a circle 10 be described with tha
greatest radius Of curvature. w
The launches, to be filed in with good rubbie mason.
r.y, laid IN mortar to a height that shall be sufficient, In adj
diion to the weight of the dead wa together with
that OF the parallel brick walls over the backs, sc. to ba.
lance or equaliberate the arches.
The road way to be nine inches thick, Macamized. and
10 rest on flat stones laid on the brick spandrell walls.
me loot ways to be raised above the level of the carriage
way and tagged. The water to be carried off by su6-
cient drains and pipes over the backs Of the arches and
through the piers and abutments.
Of the pier-heads, pilas,ers of granite to be- placed.
The piers to be at least II feet broad and SO feet LONG At
the springing line, and to be 10 feet broad at low wafer.
The pier heads to be truncated semi. cones, capped-the
upper radius s feet 6 inches, and the lower such that the
pier-head shall batter l in 3 to not moro than 6 feet below
low water.
The draw piers to be % feet broad at the springing
line and to batter, as in the case Of all the other piers,
except on the side OF the draw, which is to be vertical,
to 8 feet below low water.
The piers at a greater. depth than 6 feet below low
water, to batter l in IL, and to have sufficient offsetts ali
around them.
The abutments to have the same thickness as tho draw.
piers exclusive of the thickness of the half piers. The
masonry OF the piers, half piers and abutments TO be of
rough range work of hard granite of very large dimensions
laid in hydraulic cement. The arch stones, pilasters, cor
dom and parapets to be range work, rough hammered.
The parallel walls over the back of the arches and piers to
be OF hard brick, and together with all the other masonry
above the spingiDg limo to be laid in the best lime mortar.
The timber to be used in the foundations to be yellow
pine or white oak.
The masonry of the piers and abutmonts to be carried to
me depths Indicated 6y the following table, which exhi-
bits also the depth of the alluvial deposit at distances Of
lloi'et proceeding from the Washington abutment.