Forming Openings, Projections, and Recesses
Openings, doorways, and ductwork are formed by taking out entire sections of sheathing. Also, keyways, anchor plates, and threaded inserts have to be placed into the forms while the concrete is being poured. The vertical placement of these items is measured by the use of marker rods. These rods are separate from jacking rods and rebar but are placed in the concrete at the beginning of the slipforming. They are used to mark the vertical progress of the job and to indicate when to place any type of inserts or blockouts. The horizontal placement of these blockouts and inserts are indicated on the inside sheathing of the forms themselves. Different colors of tape are used to indicate the center of different types of blockouts and inserts. These blockouts and inserts are tied to the rebar with No. 9 wire to prevent their movement while in the forms. When blockouts are to be placed where
jacking rods are, the rods must be adequately braced against buckling. Repeated blockouts are a major design factor in the placement of the jacking rods.