Placing bar joists relative to top of steel elevation

[david_spehar]

This may be more appropriate for Revit Structural but I'm working in Building. We currently establish a level for top of steel and place framing at that level. Bar joists don't adjust for the bearing seat and we have to pick each instance and change its level offset to 2 1/2". Is there an easier (or more correct) method? What about establishing work planes?

[sbrown]

You would need to modify the bar joist family to have the ref/ at the seat instead of the top of steel as it is currently constructed. To me its just as easy to select all the bar joist and give them an offset the thickness of the seat.

[david_spehar]

I was just playing around with creating a reference plane with a 2 1/2" offset from the top of steel level and naming it "Joist T/Steel". Then when I go to place my joists I can select the plane in the pulldown menu instead of a level. It seems to work but I'm not familiar enough with work planes to know if I'm setting myself up a big fall down the road. Any thoughts?

[sbrown]

thats a perfectly good solution, you can even place a dimensionfrom you level to the workplane and lock it so if you change your top of steel the workplane goes with it.

[david_spehar]

Nice. One step closer to unlocking all of the hidden powers of Revit (I feel like Maxwell Smart walking down that hallway with all of the doors). Thanks for the help.

[BATx2]

We've run into a problem that is sort of related to this old thread.

Our problem is happening in both RAC2008 and RST2008. We have placed most of our structure in a couple of projects. For the most part the architects originally placed the structure and now the Structural Engineers are making changes (though in some cases the SE's have placed the structure and are having the same problem). We are using only unmodified out-of-the-can structural families.

When placing K-Series joists, the top of joist comes in at the same elevation as the top of beam (which is placed at a specific level). This is annoying since the joist needs to bear on the top of beam. Typically to correct this we select the joists and give both ends an offset of 2.5". The problem we run into is if the beam that a joist is resting on is modified by changing it's height offset (or some other types of alterations) the top of joist reverts back to the top of beam elevation ... i.e. if the joist offset started at +2.5" then one of the beams was set to a -12" offset at both ends the joist offset is reset to -12" instead of the desired -9.5" (2.5" above the top of beam).

Has anyone come up with an appropriate solution to this? Mainly the offset reverting problem, but if there's a good way to modify the joist family so the insert point is at the bottom of the joist seat instead of top of joist, that would probably be even better.

I've attached a small revit project that shows the problem.

Has anyone come up with an apropriate solution to this? Mainly the offset reverting problem, but if there's a good way to modify the joist family so the insert point is at the bottom of the joist seat instead of top of joist, that would probably be even better.

[david_spehar]

The problem we run into is if the beam that a joist is resting on is modified by changing it's height offset (or some other types of alterations) the top of joist reverts back to the top of beam elevation ...


Yeah, we ran into the same problem on a project and have not found a way around it. Can't wait for someone to shed some light...