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Super Typhoon Paka

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> From: FEMCCLURE <FEMCCLURE(--nospam--at)aol.com>
> To: seaoc(--nospam--at)seaoc.org
> Cc: FEMCCLURE(--nospam--at)aol.com
> Subject: Re: Tallest Zone 4 RC Building
> Date: Sunday, December 21, 1997 7:49 PM
> 
> Eric Gillham,
> 
> I am not sure that the SEAOC Web Site  (http://www.seaoc.org) has a
reference
> or hypertext to the "Tall Buildings Council" or whatever it is called. 
You
> might try to see if the "Tall Buildings Council" or "???" has a web site
and
> then you might see if they keep records of the tallest buildings by
various
> Zones.
> 
> Were you on Guam during the recent very high winds, 235 miles per hour or
> whatever their velocity was?   Can you post a message on the SEAOC List
Server
> describing what some of the effects of these high winds were like?
> 
> Stay dry!
> 
> 
> 
> Frank  McClure   FEMCCLURE(--nospam--at)aol.com
> 
> 

Yes I was on Guam during Paka.  Paka was packing sustained winds of about
140-150mph with gusts ranging up to 190mph for the northern and central
portions of the island.  The northernmost portion of the island, where
Andersen AFB is located, received higher winds, although there is some
contention as to the accuracy of the 236mph measurement.  Destructive winds
blew over Guam for the better part of 8 hours.  Guam law requires a base
wind speed for structural design of 155mph.

The damage from Paka can be broken down into the following categories:

Infrastructure:  Guam lost power to pretty much the entire island, and
water to most of the island during the storm.  Power loss in a storm of
this magnitude is a given, since almost all of our lines are strung on
poles.  We still have a number of wooden poles on island, and many of these
came down.  It is interesting to note, however, that a fair number of
precast, prestressed, spun concrete poles also snapped off at their bases
(not foundation failures, mind you).  Water loss occurred primarily because
many of the wells run off the island power supply, so when it went so did
they.  GovGuam says that restoration of power to most of the island will
take about 3 months, give or take a month.

Hotels/Commercial structures: Guam economy is driven primarily by tourism,
so we have quite a few large hotels here, ranging from 8 to 32 storeys
(hence my initial query about zone 4 R/C structures).  Most of the hotels
are R/C bearing wall structures, with a couple of SMRFs thrown in, and two
structural steel buildings.  Some of the hotels along the shore received
damage from storm surge and wave action.  Most of the hotels received at
least minor damage due to water intrusion, and some lost sliding glass
doors which were blown in, out or off their tracks.  There was also a fair
amount of soft partition damage, and ceiling damage as well.  Smaller
commercial R/C and CMU structures fared better, although a number of older,
wooden structure lost their roofs.  Prefab metal buildings also took some
hits, with roofs and walls taken off.  A few structures were completely
demolished, including one prefab structure with CMU walls.

Residential:  At last count some 5000 people were displaced due to severe
damage/destruction of their homes.  Many of these homes were wood with tin
roofs.  This number is a bit higher than it could have been simply because
it has been a while since our last major typhoon (Pamela in 1976 with
sustained winds of 140mph, and Omar in 1992 with sustained winds of about
140mph).  Our relatively frequent storms tend to cull the pack, so to
speak, and when there is a large time gap between them, a lot of
substandard construction is put up.  I doubt that many of these residences
were engineered.  However, even engineered structures took some damage,
mostly in the form of blown in windows, doors and general water damage.  A
large number of cars were damaged, either by missles (or other cars acting
as missles), or by being flipped over.  In my condominium complex, we had 8
cars flipped over, including two Lincoln Town Cars, one of which flipped
over end for end onto another car.

I have been through Pamela, Omar and bunch of storms in between, and I have
to say that this was probably the worst in terms of wind speed.  I live in
a condo that my firm did retrofit work on after the 1993 earthquake.  It is
an 8 storey R/C bearing wall structure, and I know from having analyzed it
that it is very very stiff.  However, the structure was moving quite a bit
during the storm, similar to the movement occurring during a small
earthquake, and it was not a whole lot of fun.

I figure that it will take about 3 months for things to get back to normal
for most of the island.  The 5000 displaced persons will be waiting a bit
longer, however.  Given the relative frequency of typhoons in this area,
the damage from this one was more than usual, but not overly so.

If you want some more info on this, and a few pictures, you might try the
CNN web page.  Also, I invite other engineers on Guam (that means you John)
to add their two cents worth if I missed anything.


T. Eric Gillham PE