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RE: Standard format of submission of structural design calculations.

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Muhammad

As far as I am aware there is no standard for the presentation or format of
submitted calculations, and for that matter it maybe questionable as to
whether they need to be submitted at all. What is required and acceptable
will depend on your jurisdiction, the whims of the individual
regulator/certifier and your own personal preferences. It will also depend
on the nature and size of the project. Submissions can vary between a few
sheets of scribble to several inches of computer printout only fit to prop
the desk up. The more care taken with the submission and the more self
explanatory it is then the less likely you are to experience difficulty with
the regulator or other approving authorities.

For many small scale repetitive type projects the calculations are a waste
of paper and a waste of time, everybody knows the answer: the same as last
week and the week before that. Producing such calculations, submitting and
getting checked seems to be part of some pointless ritual. All that paper
has to be stored and managed by several parties. Producing detailed worked
calculations on first submission, to a given regulator, for such repetitive
work demonstrates capability, there after the working can be simplified or
eliminated and the inputs and outputs only presented, as long as the process
of getting from input to output is clear.

Put another way, here in South Australia (SA), neither the SA development
act nor the Building Code of Australia (BCA) explicitly requires submission
of calculations. Away from structural requirements the building surveyors
clearly carry out calculations themselves. The BCA simply requires evidence
of suitability and a simple certificate from a suitably qualified individual
full-fills that requirement. The SA development act, further requires an
independent technical check, by an independent technical expert. That is a
technical check of the proposal as shown on the drawings and written
specifications, not a check of calculations. Independence means they are not
permitted to state what is required for BCA compliance only accept or reject
the proposal. However, these technical experts keep sending builders and
drafters off to get engineering calculations to submit. Not actually the
requirement!

The real requirement is that the proposal be designed so that it is
compliant with the BCA, achieving that may require conducting calculations,
but is doesn't mean they have to be submitted for checking. To my mind
independence requires the certifier carry out their own calculations, unlike
the designer they do not have to find a solution, only accept of reject. If
the certifier rejects then the designer has to argue their evidence of
suitability; which may then involve the designer submitting detailed
calculations to demonstrate their point. (Submitting calculations before
hand provides guidance, and has a tendency to deteriorate into a process of
simply checking arithmetic and not checking relevance to proposal shown on
drawings. That is the technical certifier is not doing their job properly.)

Basically you are in the role of a Technical Lawyer presenting evidence
before a judge (approving authority) that a proposal is fit-for-function,
sufficient-for-purpose, and that permission to construct should be granted.
So consider it from the viewpoint that your structure failed and you are
presenting evidence after the fact: is it possible for someone to
demonstrate that such failure is unacceptable, and is your submission
capable of countering this. Simple compliance with a mandated code will not
do this, something has to make the code relevant and sufficient for the
purpose. (eg. Designers can choose to reject less conservative options
introduced by new codes, and stay with in their comfort zone presented by
older codes.)

In simple terms submit calculations: if they get approval then they are
appropriate, if they generate requests for further information, then the
submission needs to be improved. What works depends on who the calculations
are submitted to.

If you can design a part by inspection then the certifier should also be
able to, if they can't then you will be asked to submit more calculations.
If you design by inspection, and the certifier does the calc's and
demonstrates proposal inadequate, likewise will be requested to submit more
calculations. Of course if reduced calculations to simple lookup tables,
design curves and simple computer programs and can just get results, and
your proposal is therefore compliant, submitting detailed worked
calculations is unnecessary. If you can check something in a few seconds
then so should the certifier be so able. It is the more complicated
analytical stuff that poses the problems of presentation. Computer printouts
from 3D frame analysis software presents the inputs and outputs, but how
does the certifier check that the outputs are generated from the presented
inputs. For this purpose often the computer model is requested, not
necessarily in the original format, but exported and requiring additional
work to get into other software. (Which is actually preferable that the
check is carried out by alternative software, or other means.)

So just consider that you have just received the structural drawings, and
you are the checker, assessing whether the proposal on the drawing is
structurally adequate. For each question that you ask, is there an answer of
some description in your calculations, if not make sure there is.

With each successive submission you can attempt to reduce the content, and
detailed working presented without reducing the extent of the assessment.
For example don't need to show every algebraic expression with numbers
substituted, the expressions/formulae are in the referenced code of
practice. If you can create design tools to do the calc's quickly so can the
certifier. The certifier should have more experience with compliance
requirements and therefore their design tools should be more complete,
therefore their assessment likely to identify deficiencies you may have
missed, generating a request for further information. So depending on the
certifier and their design tools, it is clearly not necessary to present all
working.

Sorry if that doesn't clarify things. I work in an area where I keep asking
why are we producing the calculations? What purpose do they serve? Plus
there are inconsistencies, no calculations need to be submitted for access
and egress distances, and there is no way that the building surveyors make a
proper assessment with a drawing and scale rule. The structure is the only
area where the calculations appear to have to be submitted (and not by the
regulations, but the people in the system), everything else appears to be
assessed by the regulator.

I understand why I do the calculations in the first instance. I also
understand that there are builders with standard calculations for their
products and copycat builders and owner/builders haven't made such
investment, and it would be unfair for certifiers to approve based on
experience gained from the original products. Some councils keep copies of
standard calculations on file and a simple reference is all that is required
on the drawings. Others want copies of the calculations for each and every
project. Standard calc's aside there is still a large amount of highly
repetitive calculations for custom projects, calculations and consequential
results that are repeated from project to project. Some of this is tabulated
in readily available design manuals, a lot more is not, because it is
specific to individuals: persons or companies. The thing that matters is
compliant solutions which can be demonstrated to be so compliant. Producing
own in-house "design" charts simplifies design, but becomes problematic in
terms of what needs to be submitted for approval. None of which would be a
problem, if did not have to submit calculations, and only needed to
demonstrate that such has been done, and the certifier actually made their
own independent assessment.

It is therefore dependent on what you feel comfortable with, and the needs
of the audience. And what you feel comfortable submitting this week, may be
significantly different than last week. (My reports vary considerably and
some are outright argumentative and critical of the codes: I don't get
requests for further information or please explain. It's somewhat worrying!)

In essence you are part of a great experiment submit your calculations, see
what happens and adapt accordingly.


Regards
Conrad Harrison
B.Tech (mfg & mech), MIIE, gradTIEAust
mailto:sch.tectonic(--nospam--at)bigpond.com
Adelaide
South Australia
-----Original Message-----
From: Muhammad Amin [mailto:engrmamin(--nospam--at)gmail.com] 
Sent: Monday, 4 June 2007 10:41
To: seaint(--nospam--at)seaint.org
Subject: Standard format of submission of structural design calculations.

I have been working for government so far. I did not have to submit my
design calculations to anybody except my superiors. It was an informal
submission like showin my input files or showing the model geometry on
computer. Now that I have retired, I am doing private practice where I
have to submit my structural design calculations to the authorities.
The calculations include output from standard software like GTStrudl
and some programs develped by me or my friends. I will be thankful if
someone would point me to guidance on standard format/practice  of
submission of calculations and if possible a sample submission.
TIA
Muhammad Amin

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