Transactions of the American Society of Civil Engineers, Vol. LXX, Dec. 1910 | Page 3

the large pilasters. After eleven applications of the 6-ft. forms, these 23-in. sections were reversed to form the capitals, thus making these pilasters, 69 ft. 10 in. over all.
The forms of the 4-ft. belt and beading were made in twelve sections of simple segments and vertical lagging, as shown in Fig. 2.
Two sets of the outside forms were split longitudinally, as shown in Fig. 2, and used to form the small pilasters. The first set was put in place, filled, and the concrete allowed to harden. The bolts were loosened and the forms raised 5-1/2 in. vertically, again bolted up, and the second set was placed in position, bringing the top of the second set up to the bottom of the cornice. The bases and capitals of the small pilasters were moulded on afterward.
The cornice forms are clearly shown in Fig. 2. The small boxes separating the dentils are made of light stuff, and tacked into the cornice forms so that, in stripping, they would remain in place and could be taken out separately, in order to prevent breaking off the corners of the dentils. A number of outside and inside sections were sawed in half horizontally in order to provide forms for the parapet wall.
The inside diameter of the tank is 8 in. greater than the inside diameter of the base. Two sets of inside forms were split longitudinally and opened out, as shown in Fig. 2, and another small section was added to complete the circle. The remaining set was left in place to support the dome forms.
The dome forms were made in twelve sections, bolted together to facilitate stripping. All ribs and segments were cut to size on the ground, put together in place, and then covered with lagging and two-ply tar paper. The lagging on the lower sharp curve was formed of a double thickness of 3/8-in. spruce, the remainder being 1 by 4-in. pine, sized to a uniform thickness of 7/8 in. Fig. 3 shows the construction of these forms and the method of putting on the lagging.
The roof forms were made in eight sections and bolted together to facilitate stripping. All ribs and segments were cut to size on the ground, put together in place, and covered with 1 by 4-in. lagging, dressed to a uniform thickness of 7/8 in., and two-ply tar paper. Fig. 3 shows the construction of these forms. The segments being put in horizontally instead of square with the lagging, gave circles instead of parabolas, making them much easier to lay out, and giving a form which was amply stiff.
The question of using an inside scaffold only was carefully considered, but owing to the considerable amount of ornamentation on the outside, necessitating a large number of individual forms, it was not thought that any economy would result.
Fig. 4 and Figs. 1 and 2, Plate XXIII, show clearly the construction of the scaffolding.
[Illustration: PLATE XXIII, FIG. 1.--SCAFFOLDING FOR WATER TOWER.]
[Illustration: PLATE XXIII, FIG. 2.--COMPLETED WATER TOWER.]
All concrete was mixed wet, in a motor-driven, Smith mixer, and handled off the outside scaffold, being sent up in wheel-barrows on the ordinary contractor's hoist and placed in the forms through an iron chute having a hopper mouth. This chute was built in three sections bolted together, either one, two, or three sections being used, depending on the distance of the forms below the deck. When the top of the forms reached the elevation of any deck, the concrete was put in through the chute from the deck above. The chute was light and easily shifted by the wheel-barrow men, assisted by the man placing the concrete, during the interval between successive wheel-barrows.
[Illustration: FIG. 3.--FORMS FOR WATER TOWER VICTORIA, B.C.]
The concrete, except that for the roof and parapet, was composed of sand and broken rock, the run of the crusher being used. That for the roof and parapet was composed of sand and gravel. The only reason for using gravel for the concrete of the roof was the ease with which it could be obtained in small quantities, the supply of broken rock having been used up, and this being the last concrete work to be done.
The concrete used was as follows: 1:3:6 for the sub-base and taper base; 1:3:5 for the barrel of the tower and tank casing; and 1:2:4 for the dome and roof. The dome was put in at one time, there being no joint, the same being true of the roof. Vancouver Portland cement, manufactured on the island about 15 miles from the city, was used throughout the work.
Before filling, the inside of the tank was given a plaster coat, consisting of 1 part cement to 1-3/4 parts of fine sand. This proved to be insufficient to prevent leakage, the water seeping through the dome and appearing on the outside of