In the February 1984 issue of Concrete Construction, page 155, general principles for bar placing were discussed. That article explained concrete cover or protection requirements and reviewed tolerances in bar placement. This article illustrates and describes common types of bar ties.
TYPES OF TIES
There are various types of ties used when securing reinforcing bars. A snap or single tie is normally used in flat horizontal work to secure the reinforcing bars in position against displacement due to work done by other trades and by concrete placing. The wrap and snap tie is normally used when tying wall reinforcement and holds the bars securely in position so that the horizontal bars do not shift while work is done by other trades or during concrete placing. A saddle or "U" tie is more complicated than the first two described but is favored in certain regions. It is used for tying of footing bars or other mats to hold hooked ends of bars in position: it is also used for securing column ties to vertical bars. The wrap and saddle tie is similar to the saddle tie. This type can be used to secure heavy mats that are lifted by crane and for securing column ties to vertical bars where there is a considerable strain on the ties.