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RE: Standard format of submission of structural design calculations.[Subject Prev][Subject Next][Thread Prev][Thread Next]
- To: <seaint(--nospam--at)seaint.org>
- Subject: RE: Standard format of submission of structural design calculations.
- From: "Conrad Harrison" <sch.tectonic(--nospam--at)bigpond.com>
- Date: Mon, 4 Jun 2007 17:06:46 +0930
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 ******* ****** ******* ******** ******* ******* ******* *** * Read list FAQ at: http://www.seaint.org/list_FAQ.asp * * This email was sent to you via Structural Engineers * Association of Southern California (SEAOSC) server. To * subscribe (no fee) or UnSubscribe, please go to: * * http://www.seaint.org/sealist1.asp * * Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you * send to the list is public domain and may be re-posted * without your permission. Make sure you visit our web * site at: http://www.seaint.org ******* ****** ****** ****** ******* ****** ****** ******** ******* ****** ******* ******** ******* ******* ******* *** * Read list FAQ at: http://www.seaint.org/list_FAQ.asp * * This email was sent to you via Structural Engineers * Association of Southern California (SEAOSC) server. To * subscribe (no fee) or UnSubscribe, please go to: * * http://www.seaint.org/sealist1.asp * * Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you * send to the list is public domain and may be re-posted * without your permission. Make sure you visit our web * site at: http://www.seaint.org ******* ****** ****** ****** ******* ****** ****** ********
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