Best Practices for Preliminary Sizing on Drawings? 10

[Tomfh]

In the below thread on the Hard Rock failure there is a conversation regarding the problem of preliminary member sizes and details being incorporated into construction documents without undergoing proper scrutiny. Some have suggested this may have happened in the Hard Rock failure, although it's uncertain whether this is indeed the case.

https://www.eng-tips.com/viewthread.cfm?qid=511879

What are your procedures here? Do you have a practice of pre-populating sizes and details on drawings, e.g. by a draftsperson? If so, how do you clearly indicate that these sizes and details are preliminary only?

 

[WesternJeb]

I had mentioned this in the other thread.. But we require our draftsmen to populate sizes in red text (we use revit, so it is pretty easy). It can be annoying at times, and getting a set like this ready to print can be cumbersome.. But the benefit is unmatched.

 

[lexpatrie]

With AutoCAD, anything I'd draft that hadn't been sized would have no size and have a placeholder with a ?. W? for a beam, C? for a column, and so forth.

Then before you seal a drawing, you search for ? and if you find one, fix it, start the process over. I would avoid "preliminary" sizing by anybody. Or you could go W128x? or similar, but why bother? Risky for no reason, see above. Nobody can see the "history" of these designs and with a full size designation it looks like somebody designed it. Then the ding-dong who's "supervising" the work, he just seals it because there's a valid size on the drawing. It's a problem with the supervising engineer, but it's also an organizational problem that the product is being rushed and there's a desire to put "preliminary" sizes on the drawings and then somehow rely on internal processes to identify them and make sure they are checked. That process is demonstrably flawed.

I don't give one wet damn what Revit says. If you don't have a final size don't draw it.

Regards,
Brian

 

[Brad805]

We set our beams and columns to list as "BEAM" or "COLUMN" until the sizing is about 75% complete. That is easy to do with filters in our modeling software. In CAD, not quite as easy unless you are crafty.

 

[phamENG]

Haven't done it, but I think creating a dummy beam family would work. Name it "Size me, Please" or something like that. That way you can get the ball rolling with modeling and get it in there and have something to mark up, but if they tag it, it will be painfully obvious that it hasn't been sized.

 

[driftLimiter]

In revit we had a yes/no parameter called Designed?

We can have a custom tag on elements that have been designed vs have not been designed. Red text or a different tag W? or WF Beam for example.

I try not to indicate any actual shape size unless it has been designed. I might tell the architect we need 24" for our beams preliminarily.

 

[KootK]

I do pre-populate and do nothing in CAD to telegraph "placeholders".

For QC:

1) I insist that all of the designed members for a project get marked up on some document that is separate from our CAD/BIM file.

2) Prior to issuing for construction, someone compares the design markup to the CAD/BIM sizes to ensure that they match.

This is not maximally efficient but I feel that it strikes a reasonable balance between efficiency and control.

 

[dik]

I only do preliminary sizing on a *.pdf print of the drawing... it never goes onto the CAD drawing.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[Tomfh]

1) I insist that all of the designed members for a project get marked up on some document that is separate from our CAD/BIM file.

What sort of document? A hard copy? A PDF?

 

[KootK]

What sort of document? A hard copy? A PDF?

A PDF nowadays. Flattened, dated, and filed every time that it gets updated. I'm also fine with printed output from FEM software if such output would be functionally equivalent. For me, the key is that the internal record of design is not the construction documents themselves nor the underlying BIM/CAD files. Those things are in constant flux and rarely under great supervisory control in my experience.

I feel that it is functionally necessary for me to be able to show placeholder member sizes on my progress drawing now for the same reason that it was necessary in days gone by: because folks need that information to plan their own work far ahead of my final designs being ready. I used to mark up a plan with a bunch of semi-committal "W10", "W24", "Ditto". Nowadays, clients expect that same information to be modelled in 3D... so that's what I do. It's a necessity of the marketplace in my opinion.

 

[dik]

I add text to the *.pdf filename... starting with _00 then _01, etc...

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[Tomfh]

It can be annoying at times, and getting a set like this ready to print can be cumbersome.. But the benefit is unmatched.

I really like the idea, however what do you mean annoying?

 

[canwesteng]

I always do full yellow off of plans before sealing, so each beam is checked, and that is the policy at my firm. That way you shouldn't have any prelim sizing getting out IFC. Appreciate that in the AE and residential world, budgets are tight, although with repetitive framing this should be even faster.

 

[TLHS]

I have honestly started preliminary sizing things big. Most of the time I can get depth and general family of beam width right in the high level schematic planning. If I just pick on the big end for initial planning it means that if I get into a time crunch and have to do conservative validation and run with things, I'm at least starting from a safe point most of the time. Lots of my things are industrial, though, and making things look nice and solid is part of the goal.

If a designer had the first go at things, I'll have done a full highlight off of the major drawing items at some point, so I should be picking up anything I missed there.

But I also don't stamp things that I haven't either designed or been the checker on. I can see this being a problem in a design house where you have one guy stamping for the whole team rather than having a stamping engineer that's more involved at the design level.

 

[CrabbyT]

I wouldn't call out sizes without doing the calcs. Too much risk that someone will see the drawing a jump the gun.

 

[JStructsteel]

If they were building it, then it was signed and sealed. If it didnt go thru the required checking, etc. then that is clearly on the EOR.

If a placeholder must be made, then it should be such that its so obtrusive, Call them W36's or something.

 

[milkshakelake]

Echoing JStructsteel, our drafters use something ridiculous or nonexistant (W10x344, (20)#19, etc). It'll get picked up in final review. All drawings go through 2 senior engineers before being filed, and none of the crazy sizes have slipped through the cracks yet. Fingers crossed.

 

[WesternJeb]

All drawings go through 2 senior engineers before being filed

What a dream! I have to beg for a thorough review from my seniors.

 

[WinelandV]

none of the crazy sizes have slipped through the cracks yet. Fingers crossed.

On the bright side, when the fabricator can't find anyone supplying W10x344's, you're likely to get a phone call.

Please note that is a "v" (as in Violin) not a "y".

 

[phamENG]

What a dream! I have to beg for a thorough review from my seniors.

Yeah...I would make up dumb questions to scare my boss into reviewing my work. "What's a dia-frag-um, again?"