How are openings made in wall that are cast by slipforming?
The forms for openings are tied to the reinforcing steel. Obviously no protrusions beyond the wall surface can be permitted. This suspension system allows some possibility for necessary movement during concreting. The attachment is ordinarily made by welding, though no welding to reinforcing steel is allowed in nuclear plant concrete work. Large section of the wall can be blocked out as openings by bulkheads which are temporarily fitted into the slipform itself and move with it. The technique can be used to cast stepped-down walls, to add pilasters, beams or columns or remove them, or to put in pockets for beams, keys or dowels, or slots for attaching masonry.