How much tying wire do you need?25-10-2019 | W. van Wijngaarden
We are regularly asked how many coils of tying wire are needed when the order is placed. To help you to estimate a correct amount of tying wire, this article focuses on tying reinforcing steel and provides a practical guideline for calculating the amount of tying wire.
When placing the reinforcement it is important that the reinforcing steel remains in the right place when it is walked over and during the pouring of the concrete. To ensure this, ties are made at the level of crossings and overlaps of the bars with tying wire. The tying also prevents the flying ends of reinforcing mesh from ending up in the coverage and forming rust here. By making sufficient connections with tying wire, sufficient rigidity of the reinforcement construction is achieved. Furthermore, in general:
- The greater the load on the reinforcement, the more ties required,
- The larger the diameter of the reinforcing steel, the fewer ties required.
Types of tying wire
For the tying, annealed wire of 1.24 millimeters is used. There are coils of tying wire for sale of 1.5 and 5 kilo which have a length of 160 meters and 530 meters respectively. Annealed tying wire will rust when it comes into contact with moisture. If this is not desirable, for example when installing floor heating mesh or processing stainless steel rebar, it is advisable to use galvanized or stainless steel tying wire.
Tools for tying
Tying rebar with a wire cutter is labour-intensive and a considerable burden on the forearm due to the repetitive turning movement that must be made. As a solution for this there are double loop ties. With the help of a double loop tying tool tying is easier and faster.
Using the tools
The hook of the device is inserted into the eyelets and by making only a pull the wires are twisted together. No wire has to be cut now either.
Types of ties
There are different types of ties that can be used. The snap tie, saddle tie and cross or figure-eight tie are mainly used. The snap tie is the quickest to make and is used the most. The saddle tie is used when connecting a straight and a curved bar that cross each other. However, if a situation requires a stronger connection, the figure-eight tie or one of the three techniques is made with a double wire.
The strength of the ties
The final strength of all three ties is achieved by tightening the wire well and twisting it two to three times before the wire is cut. Make sure that the cut wire does not protrude to prevent injury and not stick out of the concrete.
Practical guideline for the amount of tying wire
To estimate how much tying wire will be used during a project, we have established some rules of thumb to calculate the number of ties. These rules of thumb have been drawn up through experience in practice and are therefore not binding recommendations. The table below shows how many ties will be made per product. For a snap tie, assume a wire length of 12 centimeters. By multiplying the number of ties with 12 centimeters, you can calculate how much tying wire you will need.
Method of calculation
Because reinforcing mesh without flying ends are less suitable for use in floors, they are not included in the table below. For a construction with a single layer of reinforcing mesh, each flying end must be provided with a tie at the end. When laying the floor with a double mesh, at the outer reinforcement bar (1st layer), each flying end must be tied at the end and the flying ends in the 2nd layer approximately every 450 millimeters. Because in the case of double mesh, therefore, not every flying end is tied, the number of flying ends of a reinforcing mesh is multiplied by 0.9 for the calculation of the number of ties. With this method of calculation, the number of ties may be slightly higher than in practice (it is possible that the ties are made every 450 millimeters on the long side), but this way you will never have a lack of tying wire!
Guideline by separate parts
If products are assembled from separate parts, the following applies:
- When making a beam, footing cage, column or U-link cage: a tie at all corner crossings, at other places every 500 to 600 millimeters (depending on the link distribution)
- For floors and walls: at the edges all crossings and at
- wire spacing / centre-to-centre (ctc) 100; every 4 crossings (500 millimeters)
- wire spacing / ctc 150; every 2 crossings (450 millimeters)
- wire spacing / ctc 200; every other crossing (400 millimeters)
- for larger mesh sizes, all crossings
- Always tie the end of a bar to prevent it from sticking out of the concrete after pouring the concrete.
Contact us for your questions
Do you still have questions about tying rebar or other questions after reading this article? Please contact us, we will gladly help you further.