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RE: ASCE 07

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David, Richard

The discipline that brings all that together is called industrial
engineering.

The points you raise are an issue I have with the coldformed steel shed
industry, and various other manufacturers of what are perceieved as
pre-engineeered and manufactured structures: things bought off-the-shelf.
Where basically the sales person is designer and the documentation is
scribble on back of an order form. The calculations that got the industries
started are less than complete, but each manufacturer put's a 1000 or more
in the built environment each year.

Whilst engineers may make mistakes, there is variablility in those errors
from one building to the next. As they gain experience expect the
design-quality of the buildings to improve. But not with the manufactured
products the design is locked in, no changes occur, until the codes change,
and are more explicit about the assessments made. Whilst the Building Code
of Australia (BCA) is revised every year, the structural codes referenced
may only be revised every 10 years or so. So for example no real mandatory
requirements on thorough assessment of connections: consequently adequacy of
some connections is questionable. So the manufactured buildings with
potential defects keep being approved for specific projects, based on
standard calc's, and not neccessarily relating to the project. For example
calc's for a 9m span shed could be used for an 8m span shed, other
parameters being equal. Such things like using 12m span calc's for 11m span
shed of greater height typically gets picked up, by certifying authority for
project. But then some consulting engineer has to provide calculations for
the project: and its like how did they make the original shed work?

Or take an aluminium balustrade. Don't have aluminium structures code, but
just a metal. So size some anchor bolts and complete penetration butt weld
existing post design to base plate: job done? Hopefully certifiers think
otherwise. Problem is go out buy specific materials code, learn its
approach, and becomes first and last time see projects of that nature. And
yet would think a manufactured product has superior engineering, testing,
and product development behind it than a custom built insitu structure.
People buy these things because they think they can avoid delays with
design, but experience more delay because they introduce custom features and
the suppliers do not have engineers on staff: well no technical people
really.

I think there needs to be an over all code that captures everything that
needs to be assessed against established science, but which keeps everything
simple for the dominant 80%, and then references to more detailed codes for
the other 20%. There should be independent technical checks not
self-certification. (The balustrade above, was self-certified, manufacturer
came to SA where independent certification rejected it.)

Also there does need to be some rationalisation to all the paper churned
out. I don't see point doing calculations simply for submission as the
"evidence-of-suitability" required by regulators. To me the point of
calculation is to determine something I don't know: why calculate a
point-value for a project when can calculate a maximu/minimum value once in
my life. So there is a certain investment in heritage that organisations,
industries and societies acquire.

No need to keep doing the same thing over and over again. Further more get
it done in the first place by someone who knows what they are doing. Don't
want unwarranted variability in performance got to get the critical
characteristics right. Performance based codes that everything is worked out
from first principles again and again. It means have options for a far
greater variety of prescriptive design-solutions. And if published then a
greater community has opportunity to review and comment on defects to be
removed in the design.

And yes do have to design the quality in, taking into consideration the
process used to make it. No amount of inspection will get steel into the
concrete if steel is in short supply. So don't design steel reinforced
concrete structures for a region short on steel, but abundant with bamboo.
But if going to use bamboo how is it going to be assessed? And do we have
any data about the environmental loading for the region?

Because another problem with the regulations is an assumption, that simply a
matter of paperwork, go get some engineering calculations and approval will
be granted. Everything can be verified by calculation right, everything is
covered by the codes. Is a building project going to be stopped dead in its
tracks because there is a need for fundamental research? And they're making
it and getting approval so why can't I? It was approved last year, why not
now? And that local council over there approved but so why won't this one?

The approval process has a lack of consistency: and that is partly to do
with interpretation of codes and incompleteness of the code. There needs to
be a code above the building code, that says: technology this is what is
required for. That is where always start and then go to the specifics.

And the process of assessment and approval itself also has to be designed.
To a certain extent it is the process that needs improvement not the content
of the codes.




Regards
Conrad Harrison
B.Tech (mfg & mech), MIIE, gradTIEAust
mailto:sch.tectonic(--nospam--at)bigpond.com
Adelaide
South Australia
 



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