To: "INTERNET:seaint(--nospam--at)seaint.org" <seaint(--nospam--at)seaint.org>
Subject: Maybe the steel codes aren't the only complexity culprits
From: Peter Higgins <JillHiggins(--nospam--at)compuserve.com>
Date: Fri, 12 May 2000 17:09:24 -0400
I had never given foreign seismic codes much thought until you mentioned
it. The comparison is interesting, and does parallel my steel code comments
as you suggested it might.
First, my point of departure:
1) IBC 2000 landed here last week in all its glory with a resounding thud
on the table. It probably weighs 5 pounds. The seismic maps now reside on
CDROM (?!) I have yet to figure out how I am supposed to use them, and will
bless the BSSC for delaying implementation in California until at least
2002. Hopefully, by then I'll have it figured out. [The '97 UBC maps
already give me eyestrain, and I had to purchase mapping software to locate
my projects on them.]
2) ASCE 7-98 sits next to my previous editions dating back to the '70s (it
was called ANSI A58.1 then). The progression in size is interesting. Like
me, they aren't getting any thinner with age. All else considered, I do
like it better than IBC, but suspect that the two will converge soon. I
doubt the size or complexity will decrease in the process.
3) BOCA/SBC have gotten much more complex as well. Florida, bless 'em,
won't even think of a seismic code, and refuses to adopt the IBC. But,
given their geology, they can get away with it.
4) About the only code in the US which hasn't blown up until now is the
USA/NAVFAC/AF Technical Manual, and that will certainly fall into line soon
since its basis is switching from the Blue Book to FEMA/NEHRP. One never
thinks of the military as prone to simplification, but they resisted the
trend longest. I guess bureaucratic inertia won out this time.
As for foreign seismic codes, I have only experience in Japan, New Zealand,
the EU, Chile, and Canada. Of these, I can speak only to Canada with any
authority, but will give you my impressions:
1) Japanese work was in conjunction with local engineers. My reading of
(not very good) translations found that it certainly was shorter. I also
suspect that it's simpler because they believe in strength and stiffness
vs. our emphasis on ductility. It definitely is far less proscriptive. This
seems to agree with observations. Things seem to come through an earthquake
over there pretty well, or fall down with a vengeance. Just as you would
expect for strong, but brittle structures.
2) NZ doesn't really care what code you use these days, so long as it's a
good one. Their entire legal building code resides on about two pages now.
I love it. Gutsy people these Kiwis, but it works, and we should learn from
3) My EU seismic experience is zero in the higher zones where their code
becomes more proscriptive (and I've only seen that part in Italian).
However, implementing any of their regulations in steel at least, is
inherently easier due to the fact that their steel codes are more efficient
to design in.
4) Chile has its own code, but the owners want me to design to the SEAOC
Blue Book, so there's not much to report on that front. I have never seen
comments from a building department, so I presume they allow you a pretty
free hand. [This corresponds to my experience in the rest of South America
where direct regulation of engineering designs by governmental agencies is
5) Canada uses the National Building Code of Canada as their model. Each
Province adopts a locally adapted version of it. However, the only place
where they worry about earthquakes is in British Columbia (where they have
had some monsters), so my comments are limited to the BCBC. Part 4 (the
equivalent of our chapter 16 or ASCE 7) is a monumental 23 pages long. Of
that, around 8 are devoted to seismic regulations (counting the tables).
The commentary is another 5 pages with 1½ devoted to seismic. The steel
design section (our chapter 22) is 6 lines long (consisting of a reference
to CSA S16.1). Compare that to our codes, and you get the picture. Life is
fundamentally a whole lot simpler up there. [And the fact that an engineer
is rarely "plan checked" in Canada, but that's another story entirely.]
Further, their treatment of demand is universal, regardless of building
type (being governed only by site location and geology). Pure common sense
if you ask me, but a novel idea around here until ASCE 7-98. Demand is
reduced by a single factor related to the structural type and material
contained in a single table. W is defined in one place in 5 lines.
That's it guys. You're done. Now trot off, make sure you've got sufficient
capacity, and don't bother us with a bunch of gingerbread in the code.
We seem to equate complexity with progress. For all our code length and
complexity, are we safer than those ignorant, backward, Canucks (not to
mention those retrograde Kiwis)? In my view - No. First off, I get roughly
the same base shear for the same seismic acceleration zone with the BCBC as
the UBC. After that, I'm going to design the best structure I can, and hope
the code gets out of my way. That's what the Canadians (and New Zealanders)
expect, and allow, you to do.
If anyone's interested, there's a whole lot more I can say regarding how
the Canadians approach seismic safety, and building safety in general. They
do it differently up there, and we could learn more than a little from
Peter Higgins, SE