Structural Calculation Standard of Care
Structural Calculation Standard of Care
(OP)
Is there a standard, somewhere, which says what should be included in structural calculations?
For instance, if I have a a deferred submittal where the calculations are done by the Contractor's engineer, what should I expect? I received a set of calculations that calculates all the loads for a paritcular component, but doesn't calculate any capacities and doesn't compare the applied loads to anything that would show that the component is acceptable. I know as the EOR we don't need to do a line by line calc check but we typically check for gross errors.
The problem I have is that the Contractor says that there's nothing requiring them to compare applied loads to capacities. Is there any standard which says what should generally be included in calculations?
For instance, if I have a a deferred submittal where the calculations are done by the Contractor's engineer, what should I expect? I received a set of calculations that calculates all the loads for a paritcular component, but doesn't calculate any capacities and doesn't compare the applied loads to anything that would show that the component is acceptable. I know as the EOR we don't need to do a line by line calc check but we typically check for gross errors.
The problem I have is that the Contractor says that there's nothing requiring them to compare applied loads to capacities. Is there any standard which says what should generally be included in calculations?






RE: Structural Calculation Standard of Care
As for your question itself, well, that's the whole point of a safety factor, or resistance factors, if you will. He's given you the load factor, presumably, so ask him for the resistance factors. Otherwise it doesn't comply with AISC, ACI, NDS, etc.
RE: Structural Calculation Standard of Care
I would reject the submittal.
RE: Structural Calculation Standard of Care
This isn't the first time we've run into this though. Quite a few times we've had people say that the analysis is required but they're not required to document it in the calculations. We typically require "full and complete calculations." We reject and they refuse and it often takes weeks (if not months) of back and forth before they finally comply.
It would be nice to be able to point to something concrete in response to the Contractor. The closest thing I've come up with is IBC Section 1604, General requirements. It says that the design should be in accordance with LRFD or ASD, but doesn't require documentation of that.
RE: Structural Calculation Standard of Care
The contractor is using a typical ploy of extortion to get you to drop the requirements. Don't! (and it is apparent that you won't)
He's making you be the bad guy....no problem. It's apparently our job.
I've done hundreds of delegated engineering jobs and I've had the SEOR come back to me a couple of times asking for more info. I have no problem with that and provide it if possible. (I've also had a couple of engineers ask for some ludicrous things as well....not often, but has happened. For those I usually object if I've provided sufficient information for them to determine adequacy in accordance with the stated project requirements).
RE: Structural Calculation Standard of Care
RE: Structural Calculation Standard of Care
I've considered changing our specifications, but it's a shame to change specifications each time you have a yahoo that screws something up. I may end up doing it though. We have specs like that because one time 20 years ago such and such happened and we don't want it to happen again. You end up with a complicated set of specs. There was a time when everyone on a project tried to do the job to the best of their abilities with the final outcome in mind. It seems those times may be past. There was also a time when you could build a project with a minimal set of plans and nearly no specs on a handshake. That time is definately past.
RE: Structural Calculation Standard of Care
You may have instances where the delegated engineer designs an item, and then gives you the loads that it applies to the structure you're designing. In a case like that, they wouldn't normally be checking your structure for adequacy, just theirs. I'm assuming this is not your situation.
Typically, when designing as a delegated engineer, we'll generate calculations if requested to do so, and those will include major items. But not necessarily every single calculation that could be calculated, either. Part of the responsibility of being an engineer is knowing what needs to be calculated and what doesn't. But in these cases, we can and do generate additional calculations on specific items if requested.
RE: Structural Calculation Standard of Care
Mike McCann, PE, SE (WA)
RE: Structural Calculation Standard of Care
RE: Structural Calculation Standard of Care
Getting a pdf of a bunch of computer vomit isn't useful. I strongly suspect that this is intentional. "Screw them, if they want calculations, I'll give them calculations that would choke an elephant!" seems to be the attitude. No summary, no assumptions, no applicable loads, basically, some DOS based programs from the early 80's in 6 font that vaguely look like the element in question.
Sorry, venting.
RE: Structural Calculation Standard of Care
The contractor had us talk directly to their engineer, who maintained that legally he didn't have to provide anyone with calcs and his stamp was assurance. I agreed that he legally didn't owe *me* anything, but told him to talk to his client since they had a contractual obligation to provide calculations. So then I got to have fun conversations with the supplier about how their internal contractual situation with their contracted engineer was their problem, but they had agreed to supply certain things to my client.
There was lots of fighting, and I never did get acceptable calcs. We basically had to re-engineer what was supposed to be delegated work to ensure that it would be adequate.
It never made sense, since it was maybe two hours worth of math. The supplier and their engineer spent way more than two hours arguing about it and sending math that didn't appear to have any relation to what was being checked.
But yeah, I hate delegating engineering on anything we could reasonably do internally.
RE: Structural Calculation Standard of Care
When I get said pdf emailed to me the first thing I do is hit <ctrl> f (i.e. "find", i.e. the search function) and type in the work "fail". Much of the time the calcs they submitted show that their own design failed. It would be concerning if their model actually resembled reality in the first place.
The dos based software brings to mind software for mat footing design. It's amazing how long that one's been used.
RE: Structural Calculation Standard of Care
RE: Structural Calculation Standard of Care
RE: Structural Calculation Standard of Care
RE: Structural Calculation Standard of Care
If the delegated engineer has been negligent then you cannot entirely remedy that problem by reviewing calculations. You can surely mitigate the problem and possibly facilitate the negligence of the delegated engineer on the current and future projects.
RE: Structural Calculation Standard of Care
Even with all of this, EORs balk and often miss things so I still have to check both the EOR's and the delegated calculations, and it is not unusual for me to find serious errors. If something fails, it is not as if I can just pass all of the consequences to the EOR and delegated designer and go on my merry way. My company is a power utility and will definitely pay a price whether in lost generation, legal fees, or liability.
When I worked for a consultant I was very conscientious, as it seems are most people on this forum. I had no idea how many consultants give short shrift to their work.
RE: Structural Calculation Standard of Care
My gripe is the presentation. I don't think it costs more to state assumptions, give loads, define materials, etc. than just blowing and going. They're probably the same on every project. And hasn't anyone updated PEMB and wood truss software in 25 years? It would have to be cheaper in the long run to buy better software that gives a decent 21st century product than live with crap that isn't supported anymore.