How soon may forms be stripped and falsework removed from bridge decks?
ACI Committee 347 recommends that the concrete attain 70 percent of its design strength before falsework is removed and that it never be removed in less than five days after concreting. If there is more than one span the falsework should not be removed until the concrete in the first and second adjoining span have reached the specified strength. Forms under slabs, beams, girders and brackets also must not be removed until the concrete has reached at least 70 percent of its design strength. Bulkheads at construction joints should be left in place for at least 15 hours after casting. Forms for railings, parapets and ornamental work and for vertical surfaces that require finishing should be removed in the period of 12 to 48 hours after casting, depending on the weather.