On 2009/02/06, at 1:35 AM, Howard Ressel wrote:
If and when we go metric in steel design i am sure the industry will
work through some of these problems.
--
"Go for a Metric America"
Howard Ressel
Project Design Engineer, Region 4
(585) 272-3372
Dear Howard,
I have to say that I am having difficulty following this thread. It
seems to based on the idea that engineers (in the USA) are afraid of
large numbers.
You might recall that I have pointed out in the past that even
unqualified building workers here can handle (say) a room diagonal of
12 345 millimetres without a second thought as they became used to
these numbers in the first few days as they used them. Unlike some
other nations, they do not have to contend with fractions at all.
Skilled engineers here, on the other hand, are trained to use numbers
in the standard form of a single whole number with an appropriately
chosen decimal component and then multiplied by a power of 10 and they
don't seem to have any problem with this process.
I suppose that what people are dealing with here are the views of some
people who are not basing their conjectures on wide experience. I
agree with you that the metal design industry will soon work through
these issues as soon as they have some experience with the issues.
Cheers,
Pat Naughtin
Geelong, Australia
On 2/4/2009 at 3:50 PM, in message
<[email protected]>,
Pierre Abbat <[email protected]> wrote:
On Wednesday 04 February 2009 14:54:24 Howard Ressel wrote:
This was a bit back but i received a response from a structural
engineer
friend of mine and he tends to agree.
--
"Go for a Metric America"
Howard Ressel
Project Design Engineer, Region 4
(585) 272-3372
I would agree that designing steel in metric is not as user
friendly.
The steel section properties are typically mm2, mm3 or mm4 and are
very
large numbers. For example the area of a W36x230 beam shape is 68
in2
or 43600 mm2. Similarly, the bending section modulus is 837 in3 or
13700000 mm3. The larger values are not that easy to work with.
For the bending section modulus, we can say it's 13.7 liters, even
though
it's
not a volume. The second moment of area is on the order of millions
of
quartic millimeters, and since there's a 10^12 ratio between the
quartic
millimeter and the quartic meter and powers of 10 that aren't powers
of 1000
are avoided, the numbers are unwieldy. I think the solution is to
give a
name
to the quartic meter, even though I know of no other use for it, so
that the
prefix "micro" can be attached to it.
Pierre
<Howard Ressel.vcf>
Pat Naughtin
PO Box 305 Belmont 3216,
Geelong, Australia
Phone: 61 3 5241 2008
Metric system consultant, writer, and speaker, Pat Naughtin, has
helped thousands of people and hundreds of companies upgrade to the
modern metric system smoothly, quickly, and so economically that they
now save thousands each year when buying, processing, or selling for
their businesses. Pat provides services and resources for many
different trades, crafts, and professions for commercial, industrial
and government metrication leaders in Asia, Europe, and in the USA.
Pat's clients include the Australian Government, Google, NASA, NIST,
and the metric associations of Canada, the UK, and the USA. See http://www.metricationmatters.com
for more metrication information, contact Pat at [email protected]
or to get the free 'Metrication matters' newsletter go to: http://www.metricationmatters.com/newsletter
to subscribe.
