Hi all,
as the title says: Why does Revit remove the rebar cover condition when geometry gets joined together?
See example below:
When we join a beam to another beam or foundation, I still want my rebar cover in that beam to show up. Now I always need to manually change the cover constraints which takes immense amount of time.
I just want my rebars and stirrups in that beam to snap towards the rebar cover of the beam.
But it gets removed so the snap doesn't trigger.
Is this a bug?
Hi @semi
Joined elements don't show a cover because Revit considers that the concrete doesn't have an exterior face there (which is correct).
What is currently not possible, is to manually constrain rebar to a face resulting from a join or cut.
Such a face should be selected automatically, but not shown in edit constraints (e.g. a stirrup set in a beam between two columns will stretch as the beam stretches).
What are other situations where you need to have this constraint?
And are you always setting that distance where the stirrups start, based on the cover distance?
How would you expect the system to behave if the beam is joining the wall or column at an angle?
Cover distance is always respected. We use reference planes now to lock a cover of 3,5cm for example and then we can align the stirrups/rebars to this reference line.
Same thing should happen for a join in an angle: still keep that same cover:
This is how our contractors cast their concrete for a foundation beam to 2 pile caps:
You need to see everything seperately: Every contractor makes his formwork in his factory and places it as a whole on the construction site.
Below we have 3 formworks: 2 pile caps and 1 foundation beam. These get placed first ( only the reinforcements)
2nd phase is the placement of the starter bars in between. Then they make the formwork for the concrete and then they cast the concrete.
This is a major problem that still needs addressing in current versions. A similar behavior occurs when you attach a structural foundation to a wall where the two elements auto combine the cover. Any rebar within the wall will lose the bottom cover association, which is a big problem if the wall rebar is 'area reinforcement'.
Walls should not lose top/bottom covers even while joined to other concrete elements. This is not the correct construction order in the real world. For footings they are generally cast first with hooked dowels extending for the cast-in-place walls to follow. Rebar detailing as-is is much more tedious due to current concrete cover behavior as it means we can't use certain types of reinforcement in our sections.
