Civil Engineering Reference
In-Depth Information
Pier forms, Steamboat Rock,
Iowa. (Courtesy of EFCO.)
20.13
DESIGN OF FORMWORK FOR WALLS
In Section 20.8 the lateral pressures on wall and column forms were discussed. These
pressures increase from a minimum at the top to a maximum at the bottom of the semi-
liquid concrete. Occasionally in design this varying pressure is recognized, but most of
the time it is practical to consider that the maximum pressure exists for the entire height.
For convenience in construction, the sheathing, studs, wales, and ties are usually kept at
the same size and spacings throughout the entire height of a wall, as are the wales and
ties. In effect, therefore, uniform maximum pressures are assumed.
The sheathing and studs for a wall are designed as they are for the sheathing and
joists for roof and floor slabs. In addition, the wales are designed as they are for the
stringers for slabs, the spans being the center-to-center spacing of the ties.
If the wales are framed on both sides, the ties will extend through the formwork and
be attached to the wales on each side, as was shown in Figure 20.2. The tensile force ap-
