Mating half-tunnel forming with high yield strength, structural welded-wire fabric shortens construction time and saves money. An apartment project in Phoenix, Arizona illustrates how these two concepts can be merged to save both time and money. The project, Camelback Terrace, is a 184-unit development aimed at the luxury rental market. One of the several half-tunnel forming systems available was selected by the owner-developer. The particular system chosen reportedly has three aspects that distinguish it from some others: tight dimensional accuracy; clean, sharp junctures at corners; and efficient form handling.


Dimensional accuracy of the room being shaped is made extremely tight, through the use of starter walls. These walls are 3-inch-high stubs shaped by special formwork. One kind of special form is used for footings and foundations and another kind, for upper floors, is placed as the ceiling-floor slab is being readied for pour. The starter walls delineate the width of the room being built. The wall portion of the half-tunnel form butts up against and overlaps the starter wall, from which it takes its vertical alignment. This speeds up form placement and ensures that the wall is a correctly positioned, precise extension of the starter wall. (This contrasts with some other tunnel forming systems in which the forms are placed on the slab and must be sighted in.)

The decision to use half-tunnel forms in combination with welded-wire fabric is expected to pay off immediately in terms of a 5 month earlier occupancy for the developer and $100,000 savings in borrowing costs.