LOWERING PLATFORMS.
30!
the underside of the caisson, and running upon plate rails let into the floor.
A section showing the general arrangement is given in fig. 348. “The
double-flanged cast-iron rollers are 18 inches diameter, and are spaced
9 feet apart. The breadth of the caisson over the greenheart meeting
faces is 19 feet 10 inches, and the width between the granite faces 20 feet,
giving a clearance of 2 inches. A difference of head of from 3 to 4 inches
is sufficient to move the caisson from one face to the other.”*
WWWS
Fig. 348. —Caisson at Greenock.
SI
Tables are appended, with statistics of size and expenditure, relating to
typical caissons constructed in varions parts of the world.
REFERENCES.
On the subject of stresses in dock gates, the reader who desires further informa-
tion is referred to the following papers in the Proceedings of the Institution of Civil
Engineers :—
“Strain to which Lock Gates are subjeeted.” By P. W. Barlow. Vol. i.
“Strains on Look Gates.” By W. J. Kingsbury. Vol. xviii.
“Strength of Lock Gates.” By W. R. Browne. Vol. xxxi.
“Dock Gates.” By A. F. Blandy. Vol. Iviii.
“ Design and Construction of Dock Gates of Iron and Steel.” By J. M. Moncrieff.
Vol. cxvii.
Also, to a paper in the Proceedings of the Liverpool Engineering Society : —
“Dock Gates.” By W. Brodie. Vol. xviii.
* Kinipple on “ Greenock Harbour,” Min. Proc. Inst. C.E., vol. cxxx.