WELCOME BACK and thank you for watching this video Building a Jamaican Home Series: STEEL WORK FOR BELTING Tying the bars so that they remain in their correct respective positions is critical to achieve the desired strength of the completed concrete structure.
Saddle ties - Similar to the figure 8 tie, you begin by passing the wire feeding from your reel behind the rear bar, then across the front bar staying parallel to the bar. You then pass it behind the rear bar again, back around the front bar on the opposite side. You now twist the ends together, cut the feed wire, and bend the cut ends back. This tie is often used when tying rebar for walls or other vertical application where the rodbuster will actually climb on the rebar framework to access higher portions of the wall.
Stirrups - These are shaped rebar that hold the lateral reinforcement in a certain configuration, often called a cage. They create a framework that keeps these larger bars in position, and may be round, square, rectangular, or even complex combinations of shapes.
Dowels - These are usually L shapes, or straight lengths of rebar with a ninety degree bend on one end.
Corner bars - These are also L shapes, with each side of the ell the same length.
Offset bends - These range from a simple Z shape to complex angles, used in reinforcing concrete walkway steps and steps (changes in elevation) in concrete footings.
Hairpins - These are U shaped rebar that are often used to interlock two or more individual mats of rebar to give lateral strength to the concrete casting.
Do Mark the Layout Bars
Placing and keeping the bars in the right position is essential to achieving the desired strength of the completed concrete structure. To aid in this regard, use the layout bars as your reference. Make sure to mark them properly so you can differentiate them easily.
Do Use the Appropriate Type of Tie
For ordinary construction projects where the force of the concrete on rebar during its placement would be minimal, a simple snap tie would suffice in tying the rebar together. However, for other cases where the force of the concrete placement risks displacing the rebar, more advanced methods of ties are needed. The two most common types of advance rebar tie methods are Figure 8 and the Saddle.
For holding perpendicular bars firmly together and reducing the risk of racking, figure 8 is used. Meanwhile, for tying rebar for walls or other vertical constructions, the Saddle tie is used. In real-world applications, a combination of both along with other tie methods will be used depending on the nature and requirements of the rebar construction.
Do Chair Your Rebar
Chairs are extremely important in helping keep the rebar in their correct positions during construction. Once the mat has been established, the chairs will hold the rebar in place as the concrete covers it completely.
The Don’ts
Don’t Be Negligent of Rebar Configuration While the Concrete Is Placed
As the concrete is poured over the rebar, shifting can occur, putting the rebar out of alignment. To remedy this, you can support the rebar with a handled tool such as a shovel wedge to give sufficient leverage to allow it to hold its position. Alternatively, you may alter the direction of flowing concrete, so the force is applied in the opposite direction.
Don’t Place Rebar Support Too Far Apart
Rebar support has to be placed at just the right distance between them. If they are too far apart, the rebar will bend in the middle due to its weight and thus, result in more headaches for you. Another rebar support problem that may arise is that the rebar chairs, especially plastic ones, can also break due to the excessive weight put on them. Cracks can also form on concrete blocks, compromising the robustness of the structure being built.
Don’t Try to Arc Weld Rebar
To achieve proper adhesion, the welding process must be able to heat the surface of the metal rebar to the melting point, which is difficult to do on most rebar types. Only certain types of rebar with a “W” stamped on it can be welded. Even then, you must be a qualified welder and have a procedure planned to weld them.
To achieve the optimal results and avoid running into any problems, consider applying the best practices when it comes to tying rebar and rebar construction. If you found the information in this article useful, do consider sharing it with your colleagues and friends.
REFERENCE: www.wikihow.com/Tie-Rebar
southcoaststeel.com/the-dos-and-donts-of-tying-rebar/