Figure 7-13.-Joining wall form panels together in line.

figure 7-13. Figure 7-14 shows the form details at the wall corner. When placing concrete panel wails and columns at the same time, construct the wall form, as shown in figure 7-15. Make the wall form shorter than the distance between the column forms to allow for a wood strip that acts as a wedge. When stripping the forms, remove the wedge first to aid in form removal.

Stair Forms

Concrete stairway forms require accurate layout to ensure accurate finish dimensions for the stairway. Stairways should always be reinforced with rebars (reinforcing bars) that tie into the floor and landing. They are formed monolithically or formed after the concrete for the floor slab has set. Stairways formed after the slab has set must be anchored to a wall or beam by tying the stairway rebars to rebars projecting from the walls or beams, or by providing a keyway in the beam or wall. You can use various stair forms, including prefabricated forms. For moderate-width stairs joining typical floors, a design based on strength considerations is generally not necessary. Figure 7-16 shows one way to construct forms for stair widths up to and including 3 feet. Make the sloping wood platform that serves as the form for the

Figure 7-14.-Joining wall form panels at a corner.

Figure 7-15.-Form for panel wall and columns.

underside of the steps from 3/4-inch plywood. The platform should extend about 12 inches beyond each side of the stairs to support the stringer bracing blocks. Shore up the back of the platform with 4-by-4 supports, as shown in figure 7-16. The post supports should rest on wedges for easy adjustment and removal. Cut 2-by-12 planks for the side stringers to fit the treads and risers. Bevel the bottom of the 2-by-12 risers for easy form removal and finishing.

Beams and Girders

The type of construction used for beam and girder forms depends upon whether the forms are to be removed in one piece or whether the sides are to be

Figure 7-16.-Stairway form.