Formwork for Concrete Structures by R.L.Peurifoy and G.D- By EasyEngineering.net

244 Chapter Nine
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FIGURE 9-10
Forms for wall with counterforts.
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Forms for Walls of Circular Tanks
The forms for walls of circular tanks must be modified because of the
curvature of the walls. For tanks whose inside diameters are 30 ft or
more, the sheathing usually consists of 1-in. lumber, with the planks
extending around the wall, or of 5 ⁄8- or ¾-in.-thick plywood, depending
on the rate of placement and the species and grade of the material used
for formwork. The equations and procedures presented in previous sections
and in Chapter 5 may be used to determine the required size of
sheathing. See Table 4-19 for the minimum bending radii for plywood.
The size and spacing of studs and wales may be designed following
the procedures described in Chapter 5. However, the wales must be
installed flat against the studs, as illustrated in Figure 9-11. Template
rings of 2-in.-thick lumber, sawed to the correct curvature, are assembled
and, when in position, help bear against the edges of the studs on
the inside form. Template rings should be spaced from 6 to 10 ft apart
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