Submitting calculations 1

[rholder98]

To continue a topic brought up in Engg vs. Conventional Construction - residences in Florida

http://www.eng-tips.com/viewthread.cfm?qid=141657&page=1

:

I designed a restaurant in San Bernardino, CA, and the local building department used an outside consultant to check drawings and calcs. The whole project--drawings and calcs--had to be submitted three or four times before they were satisfied. They were very thorough, and annoying, as azcats said, with their check. I've also submitted projects in Florida, where some local jurisdictions required calcs, and some did not. I can understand it, if there are certain things they require that often are missed. Then there are the jurisdictions that require calcs, for no other reason, I'm certain, than to store away for ammunition should something go wrong.

Then again, I can also see a solid point in the argument that the seal and signature on the drawings should be evidence enough. Otherwise, what's the point in going through the licensing process?

Having to issue calcs, though, got me in the habit of making my calcs neatly organized and "pretty", as opposed to the chicken scratches I used to generate. Plus, like henri2 said, it keeps us honest.

 

[TFL]

sorry i did not see the new thread

eddy c,

I am talking about doing what ever calcs you feel needed to design with competance, putting them in a file and leaving them there until needed.

do i need to write down that 2X10s at 16" o.c. can span 10' in a house to make it ok?

I just think having to take the time to "pretty up" my calcs and send them in eliminates some of my efficieny by having to over document things for little perceived benefit. that being said certain things obviouly require calcs to be done regardless of the submittal required.

 

[JAE]

We had a similar (and good) thread discussion on calculations a while ago - here's the thread:

thread507-89434

 

[archeng59]

JAE, thanks for the link to the previous thread. great discussions in there.

I have worked with the State Fire Marshal in to review structural drawings as part of their plan review process. An experienced structural engineer can review a set of structural construction documents (CD's) and determine if something doesn't appear to be appropriate. in my opinion, having the calculations doesn't help me determine if the building is "safe" and meets code.

 

[TFL]

JAE,

Thanks for the link. You had a lot of great comments in the thread!!! i agree with you completely

tfl

 

[elyengineering]

One good example of why it's good to require that calcs be submitted -- keeps people honest and keeps designers up to speed with current Code requirements.

In Key West, Florida, I found that the common practice was to design, permit, and build according to perscriptive methods, none of which is allowed by the code. It's a 140-150 mph wind zone and significantly beefier lateral-load-resisting system is required.

The Florida Building Code states that in those places where an engineered design is required, calculations are required to be submitted as part of the construction documents. Further, the building official is required to examine the documents (or hire someone qualified to do so) to ascertain whether the design is in fact in accordance with the code.

We've got responsibilities with regard to our license, but they've got stated responsibilities as well. Good for prevention of honest errors and omissions; bad, of course, when the power of plan check (so to speak) is abused. Or not used at all!

I state code sections in my Engineering vs Conventional Construction thread if you want to reference.

 

[cvg]

regarding sloppy calculations - I spent a number of years checking plans mostly road, water, sewer and drainage plans submitted by developers for large tracts. (I was also working in San Bernardino) Submittals that are neat, orderly and complete always made my job easier. Sloppy submittals always got more scrutiny. And the more errors I found or the more I was unable to find the information I was looking for in the calcs, the more likely I was to send it back and ask for corrections and a resubmittal. As a plan checker, you don't have the time and patience to waste on a sloppy submittal.

 

[Dinosaur]

I have submitted calcs and I have reviewed submitted calcs, so I have been there on both sides. I have caught substantial errors. If I had only received the plans, how would I be able to tell the designer he made a mistake? "I know your plans don't show adequate reinforcement. Please send me the calcs." Answer, "We're sure there is adequate reinforcement and our contract doesn't require calcs to be submitted." Where am I supposed to go from there?

I have caught many errors. Anyone who says they are offended submitting calcs to engineers reviewing the plans are a bit too self confident for my taste. When someone points out a legitimate mistake in my work, all I can say is "Thank you."

On th other hand, I don't think we are paid adequately to prepare neat work. Given the timeframe of a usual project, they'll just have to take what I have.

 

[cvg]

As a plan checker, you do have a lower standard of care than the designer does. You can't be expected to check everything in only a few hours of work. It wouldn't make sense to completely re-design the project. But, with only a few hours, adequate documentation of the calculations makes it much easier to do the check. As far as the designer is concerned, it really doesn't matter what your client pays for your services, if you make an error or omission on your plans, you may be sued. Your insurance company will pay, but you will get hit with a large deductible for the claim. You may have to defend yourself in court. Make sure you check it and have it checked by others well before you put your stamp on it.

 

[rholder98]

Very good points. If you're confident in your work, then you don't get insulted by someone pointing out a mistake (we're all human), or simply asking for clarification. I'm always looking for a chance to improve, and to learn new things, and often that comes by peer reviews and plan checks.

All in all, I think it is a good idea to require calculations with drawings. It's not a problem for the competent engineers, and it weeds out the plan-stampers (more common than I like to believe).

 

[dicksewerrat]

The only time I ever got upset with a request for calcs. was when the person said over the phone" I don't know how to design it and won't know if it is ricght but I want your calcs anyway". what was he getting paid to do? Was he a file clerk?

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[JStephen]

Question for y'all...on doing structural analysis with software packages, what do you submit in the way of meaningful calcs that can be checked by someone else?

 

[IFRs]

That's the problem with software packages - they usually don't show their work. Or if they do, it's not presentation quality. I wind up using MathCAD.

 

[henri2]

When software packages are used, in order to prepare a calculation submittal, it is helpful to place oneself in the shoes of the structural plan checker. What would one expect in the submittal in order to perform a meaningful technical review of the calcs and do effective spot-checking?

I am sure many structural engineering associations and enforcing jursidictions have come up with guidleines for submittal of computer calculations.

 

[TFL]

I completely agree with the software packages are not produncing good reports. I use ram system. I find it very difficult to determine what sort of loads it's load generator is using for lateral forces. I really think they should work harder developing good reports or graphics that let you know how the forces are applied; so you can check your own work better. Things have come along way with computers. THe reports really shoudl look much better then a "dos" like report with a fancy header.

 

[UcfSE]

When I submit software output that doesn't look reasonably understandable, I have a hand-drawn calculation sheet and I put the software output in an appendix. Obviously with large models you cannot do that but you can at least attempt to explain yourself better. If the output syntax or graphics are hard to understand then I include a sample calculation with explanation written on it for reference.

 

[whyun]

In submitting calculations that includes massive amount of computer output, I always include a written narrative with a detailed design criteria and the purpose of the computer run. It can be quite lengthy when all the load combinations for a particular check is listed.

The narrative is followed by all of the input files, then relevant output for the design.

It is important to submit a computer file whether the plan reviewer will use it or not.

A picture is worth a thousand words. So, I tend to include a few graphic files that includes the nodes, member numbers, design element sizes etc., as many as needed to represent the design.

A good submittal not only helps the plan checker, but also the design engineer down the line. I, on several occasions, inherited projects done by former employees without comprehensive calculations. It was sort of a nightmare to decipher the calculations even with the final computer model file...

 

[RareBugTX]

I personally do not trust computer outputs, they are very hard to interpret and understand even for the designer. I agree that they can be submitted as an appendix but the core of the document should show the approach, criteria, load combinations, and relevant assumptions so that anyone could at least have an idea of the design intent. MathCad is a great tool.

 

[DJYork]

When submitting computer generated material I provide enough information for the checker to redesign the item (joint cordinates, locations, members, loads, load cases, ect). I also provide the stresses, deflections, and moment/reactions in the members. Also, generally have a page with a sketch or narritive with the item being analyzed.

 

[dpa]

I use Mathcad (plus Excel for moment distribution). I always paste any spreadsheets plus AutoCad sketches in the mathcad documents. Then I narrate the heck out of it. Partly it helps get the approvals faster but mostly I do it so that if someone asks a question a few months down the road it won't take me 8 or 10 hours to figure out what I did.

DPA