The do's & don'ts of modern reinforcement design12-05-2022 | W. van Wijngaarden
In construction, everyone has their own expertise and way of working. But if every expertise is left on a proverbial island, that creates extra work in the chain. For years, people have been working, lobbying and informing to increase the efficiency in the chain. In the world of reinforcement there is still room for improvement. When we share knowledge, we benefit as a chain, and therefore as a whole. We take the initiative by listing the do's and don'ts of modern reinforcement design.
From calculation to practice
May we throw the cat among the pigeons? The information we receive from designers is usually incomplete or impractical in terms of production, transport or processing. To be clear: we are not referring to strength calculations here. That is the structural engineer's expertise.
We are the specialists in translating calculations into a practical design, geared to the times we live in. We can do this through good contact and cooperation with suppliers and transporters. We think duplication of effort is a waste of everyone's time. We like to bridge the gap between the islands.
The don'ts of reinforcement design today:
- important information on a sketch and/or handwritten
- diameter 6 mm
- link distance of 125 mm
- different diameters for simultaneous bending
The (im)possibilities of today's production machines
There are many advantages to the latest production machines. Mesh are welded automatically. And rebar cages can be made by bending them. Files that we create for prefabricated parts, for example, can go straight into the machine, which means that there are no takeover errors. However, there are points to bear in mind:
- Link distances can be produced from 100 mm upwards, and must be divisible by 50. A link distance of 125 mm therefore, cannot be produced.
- Today's machines can handle different diameters, but bending two different diameters at the same time is difficult. So in a rebar cage with a bayonet or closed head, it is desirable that the main reinforcement at the top of the rebar cage has the same diameter. This also applies to the main reinforcement on the bottom side. A difference in diameter at the top and bottom is not a problem.
- Products with a diameter of 6 mm are less and less available at reinforcing steel processing plants and are gradually disappearing from production. We always immediately change the design of rebar cages, footing cages and link cages with 6 mm to 8 mm.
Figure 1. A modern reinforcement production machine
Information that is easy to process
It seems obvious: the more complete and clearer the information we receive, the quicker it is to convert it into a practical reinforcement design. It also saves time for the person providing the information, as we do not have to call or email them. Therefore, we cannot resist drawing attention to the fact that it is a must to provide the concrete cover and the diameter that must be applied. Furthermore, a cross-section of concrete beams that really belong to the design is nice. Instead of a standard cross-section from a library that is just not applicable.
Figure 2. It takes effort to extract the correct reinforcement information. Making an acquisition error is lurking. And the creator puts a lot of time into this.
And finally, a sketch on paper or a scan of a 2D drawing with handwritten notes scribbled on it is asking for trouble. It costs everyone in the chain unnecessary time. The digital age was not invented for nothing. Sharing an IFC with the concrete shape with a contractor or us saves a lot of work and reduces the risk of transfer errors.
The do's of reinforcement design today:
- diameter of 8 mm or more (except reinforcing mesh)
- link distance divisible by 50
- share your 3D shape of the concrete with us or the contractor as IFC
- always indicate the concrete cover and diameter of the reinforcement
Let's work together
We indicated earlier that we see great value in sharing knowledge. Not only from us, but certainly also from the other parties in the chain. We are building an online platform for this. Would you like to be kept informed? Send an e-mail with the subject 'Members only' and we will put you on the waiting list.
How do I calculate the number of The do's & don'ts of modern reinforcement design I need?
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