By Henry F. Perley, M.Can.Soc.C.E.
To provide for the repairing of craft on the Great Lakes, the
Government of Canada in 1889 commenced the construction of a dry dock
at Kingston, Ont., which was brought to completion in 1892, the plans
and specifications for which, excepting the details of the pumping
plant and engine house, were prepared by the writer.
After an examination of several sites had been made, that known as
"Powers Ship Yard" fronting on the harbour was selected,
and purchased on reasonable terms. In addition to the property thus
acquired, the lower portion of Union street, which had been closed
some years previously under an arrangement for the construction of a
dry dock, was ceded by the City to the Crown, which thus became the
posse-sor of a frontage of 400ft. on the harbour, a frontage having
deep water at but a little distance from the shore.
The site is situated between Gore and Union streets, having shops
of the Kingston Locomotive Works on one side, and those of the
Kingston Foundry Company on the other.
When taken possession of, the site was encumbered with several
buildings, the remains of an abandoned marine railway, an old wharf,
and the work that had been executed on a proposed dry dock and
abandoned, all of which had to be removed.
In determining the dimensions of the dock, it was judged that they
should exceed by a small amount those of the locks on the Welland
canal, so that any vessel which could pass through them could be
admitted to the dock, and a length of 280 ft. on the floor and 48 ft.
width of entrance were adopted. During construction, representations
were made, that the width of the entrance was not sufficient to admit
some paddle-wheel steamers plying on Lake Ontario, and it was
increased to 55 ft., such change involving the widening of the body of
the dock, increasing the size of the caisson and the dimensions of the
caisson chamber.
After cleaning the bottom in front of the site, an earthen
coffer-dam was placed, the material (clay) composing it being obtained
from the channel of the Cataraqui through the marsh above the highway
bridge. This dam failed when the work was about one-third completed,
but the break was easily filled and the work resumed.
The dock is built of limestone obtained from quarries at
Belleville, and fully up to the requirements of the specification,
which demanded that the ashlar in the altars, except in two instances,
should be built of stones 2 ft. 8 ins. In height. As stretchers could
not be less than 4 ft. in length with a bed not less in width than 1
½ times the rise, the smallest stone that could be used weighed over
three tons. The coursing of the sidewalks was carried through the body
of the work, the whole with Ό in. joints, and dressed with the fine
end of a Bouchard hammer. The backing consisted of large and well
-shaped stones of such thickness, that two courses were equal to one
course of face- work. The floor was of stone, the central 6 ft.
carrying the keel-blocks being raised 6 ins. above the dock bottom.
The foundation of the engine house, chimney and machinery were carried
up from the rock, and the floors paved with stone.
A quantity of concrete was used, composed of 6 parts of broken
stone, 1 part clean, sharp sand, and 1 part of Portland Cement.
The whole of the masonry was laid in a compound of one of Portland
cement to two of sand, mixed and used as required, each course being
grouted up and filled full with the compound. All joints were lipped
for 4 ins. from the face with a compound of 1 of cement to 1 of sand,
and neatly pointed and finished off when green.
Only Portland cement was used in the work, and a constant testing
was carried on during construction. Samples were taken from every
tenth barrel as delivered, and tested for fineness by the whole sample
passing through a 2,500 sieve. Briquettes of neat cement, after
remaining for twelve hours in the air and seven clear days in water,
gave an average tensile strength of 445 lbs. per square inch.
The quoins of the outer face of the inner invert and side walls
were of grey granite, all remaining stones in the invert being of
limestone. The granite and limestone quoins facing on the caisson
berth, and of the walls on either side, were worked with a projection
of Ύ in., and a full width of 12 ins., and act absolutely
perpendicular and in a true plane, the faces being finely axed and
rubbed down, for on these moeting faces depended the tightness with
which the caissson fitted, thus preventing leakage when the dock was
empty.
An extension of the caisson-berth forms a chamber into which the
caisson is drawn to admit a vessel. Along each side of the bottom are
heavy cast iron rollers placed at intervals, on which the caisson
rests and travels when being moved.
The width of the inner invert is 55 ft., and of the outer invert 57
ft., this difference being necessary to permit the caisson being
floated into its berth. They are built to a radius of 193 ft., and the
stones forming them are cut with radial joints. The lowest point in
the inverts is 15ft. 6ins. below zero, or the assumed average low
water level of the lake, 22 ft. below coping level, and 4ft. 6 ins.
above the floor of the dock.
Outside the outer invert, is an apron of stone 20 ft. in width, and
2 ft. lower than the centre of the invert, in which are placed granite
blocks on which the caisson can rest if at any time it is found
expedient or necessary to effect repairs in the caisson berth or
chamber, or to dock a vessel longer than the floor of the dock, or, in
other words, a vessel of 310 ft. in length.
Under the foundation of the dock bottom, are arterial drains, by
means of which the leakage from the lake is carried to and discharged
by the auxiliary pump, when the dock is empty.
Access is had to the dock floor by steps on either side at the
entrance end , and on either side of the timber slide at the head.
In the floor at the lake end is a rudder well, 2 ½ ft. long, 3 ft.
wide, and 12 ft. deep, which has proved of much service, as it permits
an easy removal and replacing of a rudder.
Sixteen cast-iron mooring parts, set in and filled with concrete,
are placed around the dock, together with six heavy, double purchase
capatans. On the dock floor are cast-iron keel-blocks capped with hard
wood, placed at intervals of 5 ft., and 32 bilge-blocks at 10 ft.
centres, which are operated from the dock coping.
The dock is filled through a culvert 4 ft. in diameter, the mouth
of which is outside the entrance works, and the discharge over the
inner invert, the whole being submerged 6 ft. below zero, and
controlled by a 4ft. cast-iron valve. Provision has been made whereby,
in an emergency, filling can take place through the emptying culvert,
which is also 4 ft. in diameter and controlled by a valve. The caisson
chamber and berth is connected by a 12 in. pipe with the auxiliary
pump, so that either can be emptied in the event of the stop-logs
being put in place.
The engine-house, which comprises an engine-room, boiler room and
dynamo room, is of stone. The chimney also of stone, and 90 ft. in
height- is placed partly within and partly without the building. Over
the engine and the dynamo rooms the roof trusses are of wood, and over
the boilers of iron, the party walls being carried up to the roof as a
safeguard in the case of fire.
The major portion of the floor of the engine room is 6 ½ ft. below
zero, or 13 ft. below coping level, and on it is placed the pumping
plant, which consists of two vertical 18 ins. centrifugal pumps, one
right-handed, the other left-handed, having discs 4 ft. 8 ins in
diameter, each operated by a vertical, high pressure engine, having
cylinders 18 ins. in diameter, and a stroke of 18 ins. The pumps are
connected directly with the engines and are in line; and by means of
clutches they can be geared together so that one engine can drive both
pumps, or an engine can drive the opposite pump.
The suction pipes, which are 22 ins. in diameter, are furnished
with foot-valves, and are led through the engine room floor to the
pumps, all joints being absolutely water-tight. The pumps discharge
through 22 in. pipes, the centres of which are 9 ft. below coping
level, or 2 ft. 6 ins. below zero, and when the lake is at that level,
the pumps operate against a head of that height. To prevent inflow
when the pumps are not in use and the dock is empty, each discharge
pipe is provided with a 22 in. valve.
The auxiliary pump and engines are placed on the upper or higher
portion of the engine room floor. This pump, which is an 8 in.
horizontal centrifugal, has a maximum lift of 31 ft. 6 ins., and
discharges 3 ft. below zero. It is operated by a pair of vertical,
high pressure engines, having 12 in. cylinders and 12 in. stroke,
which are also used to move, by means of intermediate gearing, the
caisson into and out of place. On the lower floor of the engine room
is a "Knowles" fire pump, the steam cylinder being 15 ins.
and the water cylinder 10 ins. in diameter, both having a stroke of 21
ins. This pump can be used in the event of the auxiliary pump being
disabled. A delivery pipe is carried to the outside of the building,
having a proper cap for attaching four lines of 2 ½ in. fire hose.
A "Knowles" patent duplex boiler feed pump, with steam
cylinder 6 ins., and water cylinder 4 ins., and stroke 7 ins., is
placed in the boiler room.
The boilers-four in number-are of the cylindrical, multi-tubular
type, set in brick work, with all the fittings and appliances for
their successful working. They are 14 ft. long and 5 ½ ft. in
diameter, each containing 8 ½ No. 9 W. G. lap-welded charcoal iron
tubes, 3 ½ ins. external diameter, and furnished with domes 3 ft.
high and 2 ½ ft. diameter. The shells and ends are of 3/8 steel, the
longitudianl seams being lapped and double rivetted, the
circumferential seams lapped and single rivetted. Before acceptance
they were subjected to a cold water test of 180 lbs. per square inch,
the working pressure being set at 100 lbs. Two of these boilers supply
steam enough for the main engines. The smoke flue runs along the front
end of the boilers, where connection is made with the uptakes, and is
carried to and through the party wall of the dynamo room, when it is
led downwards and under the floor to the chimney.
A boiler of the drop flue type, 9 ft. high and 4 ft. in diameter,
with 250, 1 Ό ins. by 18 ins. flues, with circulating tubes, is
placed in a corner of the boiler room, and supplies steam to the
auxiliary engines which can also take steam from the main boilers.
A travelling crane to lift 3 tons has been placed in the engine
room, and with it any part of the engines or pumps can be handled for
repairs.
The dock is closed by a caisson, built of steel, which may be
described as an irregular rectangular box with parallel sides and
inclined ends, measuring 57 ft. in length and on the inner face and 59
ft. on the outer; 11 ft. 10 ins. in width and 21 ft. 6 ins. in height.
Two keels, 4 inches by 8 inches, run the whole length of the bottom,
on the outer edges of which are inserted at regular intervals 4 by 4
½ ins. shear steel bars, properly bent , their places in the keels
being truly planed to the required curvature.
The keels rest on the rollers in the caisson berth and chamber, and
the curved bars which project somewhat beyond the sides of the keels,
are for the purpose of preserving the parallelism of the caisson while
being moved. The lower 3 ft. is of cellular construction for strength
and stiffness, and composed of ½ in. plates and 3x3x3/8 ins. angles.
All angles for the sides and ends are 3x3x1/2 in., and for the reverse
bars 3x3x3/8 in. The cross beams up to the lower dock are 4x4x1/2 in.
angles, and above 3 1/2x3 1/2x ½. Under the lower and upper floors, Z
beams 5 x 3 1/16x2 3/4x1/2 in. were used. The upright posts are
6x3x3/8 in. channels, and the diagonal braces, 4 x 3 x ½ in. angles.
The plates in the bottom and first row on the sides and ends are ½
in. in thickness, and those above diminish to Ό in. in the top plate,
which is finished with a 9 x 3/8 in. bulb. The floor plates are ½ in
thickness. All outside plates were planed on their edges and lapped 2
½ ins in the work and were single rivetted. Where required, filling
pieces were placed between the plates and the frames, to make up for
the difference in the thickness of the plates, and voids between the
plates, and frames.
For the movement of the caisson a hauling bar 13 ft. 4 ins. in
length is connected by means of a 4 in pin, the outer end projecting 7
ft. 9 ins., and carrying a yoke of 17 ft. 8 ins in length attached by
a 4 in. pin, the outer ends being supported by two hinged brackets
coupled with parallel motion bars.
For ballasting purposes, two 6 in. sluice valves are placed in the
outer face above the line of the upper floor, to which are attached 6
in. cast iron pipes leading to within 4 ½ ft. of the bottom. At the
bottom of the inside face a 4 in valve is placed to drain the caisson
when the dock is empty; and the caisson can also be emptied by a No. 5
pul-ometer.
The cellular bottom is filled with concrete, and the further
permanent ballast is supplied by the requisite amount of stone.
On the outer faces are rivetted 6 x 6 x ½ in. angles which carry
the white oak meeting faces, which are secured in place by Ύ in
bolts.
The caisson weighs 255,000 lbs., and when the lake is at zero its
displacement is 358 net tons. It is moved into and out of place by
wire ropes, which pass over traversing grooved wheels secured to the
masonry at the dock end of the chamber, and over spirally grooved
drums keyed on a horizontal shaft at the head, which is actuated by
the auxiliary engines.
The dock at zero contains 2,100,000 gallons of water when
unoccupied by a vessel, and can then be emptied in 75 minutes, the
pumps and engines making 175 revolutions per minute, each pump thus
throwing 14,000 per minute. Through the filling culvert the dock can
be filled in 55 minutes.
A large portion of the dock property as it stands today is made
ground, the area being enclosed by crib-wharfing of the usual type,
and filled with the materials excavated in grading the site, and from
the dock pit.
The cost of the dock may be placed as follows: -
Land
.
$ 20,000.00
Dock Proper
. 365,000.00
Pumps engines, etc
.. 26,000.00
Engine House
.. 26,000.00
Caisson
. 18,000.00
Engineering and contingencies
42,000.00 ___________
Total $497,000.00
DISCUSSION
Mr. Perley, in reply to questions which had been asked, stated that
the dock was founded entirely on rock, and no piles were used in its
construction.
Only a comparatively small quantity of concrete was
used-principally under the floor of the dock, where the thickness
averaged 18 inches, and in places where it was desirable to equalize
the roughness of the bottom and make an even foundation for the
masonry.
The projection downwards in the longitudinal section, and the
section looking lakeward represents the position, etc., of the rudder
wall.
A plan of the coffer dam cannot be furnished, as there was not any
in existence . According to the specification the dam was to have been
either a crib-work or a pile structure. After the commencement of the
work it was proposed to substitute a dam of clay enclosing the area
required, as piles could not be driven, and there might be a
difficulty in maintaining a tight joint under a crib work structure.
Clay was therefore dumped into the lake and carried up 4 or 5 ft above
zero.
The failure alluded to was caused by the washing away, during a
storm, of the dam at a weak
point at water level where settlement had taken place, thus making
a gap through which the lake water flowed. A few sheet-piles, and a
small quantity of clay stopped the breach, and the dam, thus repaired,
remained intact until the work was completed.
Thursday, 23rd April.
HERBERT WALLIS, President, in the Chair
The discussion on Mr. Perleys paper on the "Dry Dock at
Kingston, Ont.," and on Mr. Carrolls paper on "The
Effects of Engineering Works on Water Currents," occupied the
evening.