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

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Forms for Walls 213
5. Top plates are installed and fastened to the tops of studs as parts
of the panel frames.
6. Bottom plates are installed and fastened to the bottoms of studs
as parts of the panel frames.
7. Sole plates are placed and fastened along each side of wall footings
to provide initial alignment and support for wall forms. Also, the
use of sole plates permits easy use of form ties near the bottom of wall
forms.
8. Braces, fastened to one side of the forms and to stakes set in the
ground about 8 to 10 ft apart, prevent the forms from shifting when
the concrete is placed. If the sole plates are not securely fastened to
the footing, braces should also be attached to the bottoms of the forms
on one side of the wall. Screw-adjusting braces are commercially
available which allow fast and accurate aligning of forms.
9. Form ties, with a clamping device on each end, are installed
through the forms to resist the bursting pressure exerted by the concrete.
Some are equipped with devices which enable them to serve as
form spreaders or spacers. Many types and sizes are available, with
allowable working strengths varying from 1,500 to 50,000 lb or more.
The common strengths of form ties are 3,000 and 4,000 lb. Form ties
provide support for the wales.
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Designing Forms for Concrete Walls
Forms for concrete walls should provide sufficient strength and
rigidity at the lowest practical cost, considering materials, labor, and
any construction equipment used in making, erecting, and removing
them. The designer should know the magnitudes of the forces that
act on the component parts and the strengths of these parts in resisting
the forces. Chapter 3 presented pressures and loads that act on
formwork.
The strength of lumber varies with the species and grade used for
formwork. The allowable unit stresses in bending, horizontal shear,
compression perpendicular to the grain, and compression parallel to
the grain vary with the species and grade of lumber (see Chapter 4).
Each design should be based on information that applies to the allowable
unit stresses for the species and grade of lumber used for the
formwork.
As presented in Chapter 5, many calculations are required to
determine the adequacy of the strength of formwork members. It
requires considerable time to analyze each beam element of formwork
to determine the applied and allowable stresses for a given load
condition, and to compare the calculated deflection with the permissible
deflection. For each beam element, a check must be made for
bending, shear, and deflection. For simplicity in the design of
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