Q.: We've been trying to think of a way to standardize and simplify the job of tying up reinforcement cages for columns 18 inches square. There will be a large number of columns, and we would like to develop an assembly system that minimizes the work.
A.: You might investigate the use of welded wire mesh. This is widely available in flat sheets. In one direction the sheets have the needed amount of steel area and the right spacing for ties. In the other direction they have just enough wire to stiffen the cage. It is said that, when the sheets are bent on a job bender to form cages, it saves about 75 percent of the labor that might otherwise be used for tying up rebars. This system is reported to work well for lightly reinforced columns. In heavy columns welded wire can be used as cages in combination with vertical rebars.