The Atlas handbook on concrete construction

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1920 Excerpt: ... is made at the top of the column by fitting in triangular pieces of wood. Since fresh concrete is practically liquid and over twice as heavy as water, the column form must be designed to withstand the bursting pressure of the concrete. This will make it necessary to have the yokes closer together at the bottom than at the top. In place of bolts, rods with a malleable iron clamp fastened in place with a set screw are often used for form work. These clamps may be obtained from supply houses. The clamp is slipped over the rod and brought to a firm bearing by a device furnished by the makers of the clamps. Then the set screw in the clamp is tightened, holding the clamp in place. In the same figure is shown a method of clamping columns by using a chain. The chain is hooked around the column as tight as possible and the slack taken up with wedges. Table 17 gives spacing of yokes for various sizes and heights of columns. When column forms are very wide, larger yokes must be used or bolts placed through the center of the column. Exterior column forms require different treatment as one side must project over the edge of the building. Such a column is illustrated in Figure 76 and 77. The'two bolts shown at the top of the form are left in the concrete with TABLE 17 Spacing of yokes for columns. How to use Table: To find spacing of yokes for a 21" x 18" column 10 feet high, use column headed 24". Read up column from 10' line and the spacing of yokes will be found--14' for bottom yoke, 16" for next upper yoke, 22" for next, and so on to top. the ends projecting. To these bolts are fastened blocks to support the overhanging sides of the form. The bolts are removed later by turning out with a wrench. Stud bolts are put in the floor, when it is so...