This article from this month’s Engineers Australia magazine is by a young design engineer who talks about the importance of site visits for inexperienced designers. Visiting a construction site where your design is being constructed can be a steep learning experience.
The biggest point he alluded to is constructability of the design. By that I mean that whatever you design needs to be able to be built. If it’s too complicated or fiddly or downright impossible, you may experience some of that “slightly more descriptive” language that was mentioned. But don’t take offence at that (that’s just how they are) – use it as a learning experience.
I’ve experienced the particular example given where a reinforcement steel fixer complains that they are unable to construct a unit as it is shown in the drawing. There are a few things structural designers need to consider when designing reinforced concrete / precast units (for reinforcement in particular).
- N32+ size rebars are very heavy to carry. If you have a concrete unit say 18m long and this bar is to go on the top of a 1.5m high wall, you might need 5 steelfixers to carry it and hold it in position while it is being tied. If there is the possibility of using more of a smaller size bar, do it, purely for manual handling reasons. Obviously if it doesn’t give you the required capacity you can’t, but at least consider it.
- Reinforcement does not come bent at a sharp 90 degrees like it is drawn on the design drawings. When it is made, reinforcement is bent around a pin so it has a radius – there is a curvature. If you have double layer reinforcement in a unit, this could make things very unpleasant for the steelfixer.
- You can’t have 2 x 90 degree bends in close proximity to each other. In practice, as mentioned above, this is made into a U-bar around a pin to suit. So when you are dealing with pull-out bars that have to be flush with the face of the concrete, it might not always be that easy.
- Don’t have too much reinforcement in one location! You have to realise that when the concrete is poured, it has to go between and bond with the reinforcement. If it’s designed such that you have a wall of reinforcement, well it’s just not going to do what it is supposed to.
Why Construction Workers Should Wear Long Sleeve PPE
