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Re: WOOD AND HOUSES

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Date: Mon, 24 Aug 1998 20:07:49 PDT
 From: "Jose Diez" <josediezpe(--nospam--at)hotmail.com>
Subject: Re: WOOD AND HOUSES
To: seaint(--nospam--at)seaint.org
> -----------
> The mechanical engineer likely referred to concrete masonry blocks 
> instead of bricks.  Clay is a rare find in Florida (other than in the 
> Panhandle). 
> snip
> Unfortunately, the use of masonry needs special treatment in earthquake 
> prone zones.  Steel can carefully replace masonry, ------ snip

Concrete masonry was quickly converted to hollow block units and reinforced.  
Not so much a matter of steel replacing masonry but utilisation of the 
advantages of both materials.  Clay brick work is also reinforced. 

> Have you ever browsed a fire code in a Roman system country??? It is 
> only a few pages long, compared to the multiple volumes of NFPA codes in
> the US.

Agreed, fire codes are voluminous, so long as you cannot use separation 
distances to prevent spread.  We are fortunate to use residential detached 
dwellings on 700 plus square metre lots.  Hence wood construction is OK.

snip
 
> Uplift is another word I rarely heard in my practice in Roman countries.

In NZ, because we are mostly pioneer stock and the mainstay is farming, we 
have saying related to "doing anything with number 8 wire!".  In wood 
construction this extends to the use of short wire 'dogs' as uplift 
resistance (together with metal straps etc.)  Easy and cheap!


>  
> If you have a roof slab 4" (100 mm) thick that is 48+ PSF. The net 
> uplift under extreme winds for low rise buildings in the Caribbean area,
>

In earthquake country, concrete slab roof on unreinforced masonry eventually 
equates to squashed people.  Not good.

> 
> One of my main reasons to move from Canada to the US, was that nearly 
> every affordable building was built out of wood. Today I can afford to 
> live in a concrete hi-rise structure.  I love noise,  carbon (ollin for 
> those who understand spanish) and people.  I am really tired of living 
> among cows, wood, and having to travel to downtown for work. Just 
> because after 1965, the americans decided to abandon urban life!
> 
> I AM VERY URBAN! And proud of it.

Each to his/her own.  Remember the grass, the flowers, the trees, the song 
birds, the rippling streams, the quiet?  How long since you have seen the 
bright stars of the heavens not dimmed by the lights of human habitation?

> Have you ever wondered why the roman 
> coliseum is still there? Or perhaps the house where Pilatus was born 
> more than 2000 years ago is still there?? Many other important buildings
> have lasted2 milleniums or close to it, just because they were not built
> in wood.

What is the Coliseum used for now?  Is it functional? (Yes it is a wonder 
and magnificent.)  But reality is the needs change and functions change.  I 
don't like it but planned obsolescence is upon us and extends to the built 
infrastructure.  How adaptable are large mass masonry buildings?
We have just constructed our national museum.  It has a DESIGN life of 500 
years.  Loadings and material selections reflect this.  It is built in high 
quality reinforced concrete on base isolation. Features include large open 
structural spaces adaptable to infill construction for variable use over 
time.  Some Roman genes in NZ somewhere??

> By the way, some ancient roof structures were made out of wood. 
> How come most of these ancient roofs have little or no leaks??  Is the 
> english-american system of bio-degradable materials any better than the 
> Roman system??? NO!

Oh?
 
> Jose Diez P.E.  FL.
> 

Previously I did not refer to the economics of residential construction in 
various materials.  Yes we do have inner city living for those who prefer 
it.  But our city are less than 500,000 people maximum, usually less than 
350,000,  and (with exceptions) building heights generally less than 10 
stories.  Reinforced concrete and steel then become the economical 
construction forms.

But our environment is conducive to urban and rural living and more prefer 
this.  Detached single family dwellings represent some 50% of the value of 
built infrastructure and 67% of the buildings.  Add 10% to the cost of 
housing construction and we have a major economic impact which quickly 
translates to the individual wanting to buy a home.  You seem to have 
experienced this in Canada?

Again,  each to his/her own.  This diversity ensures continuity of the human 
race has more probability.

Cheers, Bruce S

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Bruce Shephard, Principal Consultant Seismic Risk
Opus International Consultants, New Zealand
DD Telephone +64 4 4717597,  Fax +64 4 4711397
Email bruce.shephard(--nospam--at)opus.co.nz
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