Assuming the fabrication to be done in the field, the mode of procedure will be as follows: Order the bars or rods to be shipped in bundles of corresponding sizes and lengths of pieces with each bundle tagged with its proper shop number or mark. The bundles should weigh about 200 lbs.; this is a load easily handled by two men and so long as possible all handling should be done in the original package, for when once broken it is very hard to get men to carry a full load. As received, the bars of each size and length should be stored by themselves. For ordinary bars not having long prongs a rack of the general form shown by Fig. 207 serves the purpose excellently. When a great deal of metal must be kept stored for some time it is wise to roof over the racks, not only to protect the metal from rain and snow, but to enable the men to work dry shod in stormy weather. Usually it will pay to have one man whose sole duty it is to receive and check all metal and to attend to its systematic arrangement on the racks; this same man will also direct the removal of the metal to the shop where it is bent and otherwise worked up, and can, if he is competent, earn his pay many times over in time saved all along the line in handling and working up the reinforcement. The authors have seen enough time wasted in hauling over and rehandling metal in piles to get at what was wanted to pay for shed, racks and the wages of a storekeeper several times during a moderate sized job. In large work provide the storekeeper with a schedule showing the order in which the metal is wanted for the work so that he can arrange it in that order and can check up his receipts from the mills and report missing items in time for the deficit to be made up before some part of the work has to be stopped because of material missing. System in receiving and storing the metal is absolutely essential to rapid and accurate work at the bending and erecting tables.
The work done on the metal consists chiefly of bending. The metal can usually be bent cold, but for sizes 1½-in. and upward some makes of bars require heating; this can be done by laying the bars side by side on the ground and arranging sticks and shavings on top of them in a strip 18 ins. to 2 ft. wide across the portion where the bend is to be. Only moderate heating is usually required. Ordinary bending is a simple process and can be done with very simple apparatus. Figures 208, 209 and 210 show frequently used devices, any of which can be made by an ordinary carpenter. For heavy bars, 1½ and 2 ins., the device shown by Fig. 210, with its heavy, swinging beam, is particularly efficient. An example of more elaborate methods is had in the following description of the processes employed in fabricating girder frames and hooped column reinforcement for a large factory building. The building was 500×75 ft., with six stories and a basement, built for the Bush Terminal Co., Brooklyn, N. Y., in 1905. Three longitudinal rows of round columns and two rows of rectangular wall columns carry heavy longitudinal girders supporting floor slabs with corrugated undersides as shown by Fig. 211, which also shows the floor slab reinforcement. About 12,000 cu. yds. of concrete and 1,000 tons of reinforcing steel were required; hence 167 lbs. of steel were required for each cubic yard of concrete. The floors, however, were designed to carry a load of 800 lbs. per sq. ft. The particular feature of interest in this building was the fabrication of all the column and girder reinforcement into unit frames and cylinders in temporary workshops on the site.
Fig. 208.—Table for Bending Reinforcing Bars.
Fig. 209.—Table for Bending Reinforcing Bars.
Fig. 210.—Table for Bending Reinforcing Bars.