Fig. 205.—Sullivan's Plank Holders for Wall Forms.
A type of wall form construction intended to do away with studding and bracing is illustrated by Figs. 205 and 206. In both cases metal plank holders are used in place of studs, and practically the only difference between the two is in the shape and material of the holders. The mode of procedure is to work in horizontal courses one plank high around the wall, removing the bottom plank and placing it on top as each new course is begun after the first few courses have been laid. Using the arrangement shown by Fig. 205 in constructing a building 100×54 ft. in plan and 36 ft. high with 12-in. walls, a height of two 12×2-in planks was all the form work that was ever necessary at any one time, so that the amount of form lumber required for the building was 2,464 ft. B. M. plus 205 ft. B. M. of 2×4-in. flooring strip, or altogether 2,669 ft. B. M., or 0.24 ft. B. M. per square foot of exterior wall surface, or 6½ ft. B. M. per cubic yard of concrete. This same form lumber with 16 additional plank was then used to construct a building 100×100 ft.×16 ft. high, so that some 3,000 ft. of form lumber sufficed for 17,548 sq. ft. (exterior surface) of wall or for 617 cu. yds. of concrete in 12-in. wall, which gives 0.17 ft. B. M. per square foot or 4.8 ft. B. M. per cubic yard of concrete.
Fig. 206.—Farrell's Plank Holders for Wall Forms.
ERECTING FORMS.—The organization of the erecting gang will depend very largely on the manner in which the forms have been constructed. If they have been constructed in sections which go together with wedges and clamps common laborers with a foreman carpenter in charge to direct and to line and level the work will do the erecting, but if they have to be largely built in place carpenters are necessary for all the work except carrying and handing. There should be at least one foreman for every 15 to 20 men and a head foreman in charge of all form work. The mode of procedure will differ for every job, but the following general directions apply to all work in greater or less measure.
Clamps, bolts and wedges and not nails should be used wherever possible in assembling parts of forms in erection; these devices are not only quickly and easily applied in erection but they are just as quickly and easily loosened in taking down forms and they can be loosened without jarring the concrete member.
Lining girder forms and lining and plumbing column and wall forms is high-class carpenter work and should be directed by competent carpenters. A column or girder which is out of line or plumb not only looks bad but may be required to be removed and corrected by the engineer. The expense for one such correction will be many times that which would have been involved by proper care in the first place.
Supports or staging for the forms should be used freely and well braced in both directions. Uprights should be set on wedges and bear against a cap piece and on a sill piece to distribute the load.
Erect, line and plumb the column forms first; then erect, line and level the girder forms and set the girder staging, and finally erect and level the slab centers and their supports.
Leave the foot of each column form open on one side at the bottom so that the column reinforcement can be adjusted and connected up and so that a clear view can be had through the form to detect any object that may have fallen into the form and become wedged; this same opening makes it possible to clean the form.