The period of time after which forms may be removed varies according to
conditions. Rich and dry mixtures set quickly, and warm weather tends to
hasten the setting of concrete. The character of the structural member
and the loadings also must be considered.
Thus, an unloaded wall 12 inches or more thick may be stripped of forms
in from 1 to 3 days, while the forms of thinner walls should remain in
place from 2 to 5 days. Slab forms and the sides of beam and girder forms
may be removed in from 6 to 14 days if the span is not over 7 feet. The
bottoms of beam and girder forms, even though of a span less than 7 feet,
should remain in place and braced form 10 to 14 days and even longer.
Experience is the best guide to the time of removal, but if there is any
doubt ample time should be allowed, especially in cold weather.
[Illustration: Fig. 3.--Suggestion for circular form.]