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Re: Minimum Temperature Reinforcement

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Actually ferrocement can be quite labor intensive.  It also requires
numerous - 4 to 8 layers, of wire mesh, 3/8" to 3/4", but chicken wire has
also been used.

The actual cement strengths can be around 1000 psi.  Folded structures can
be made.  We constructed and tested ferrocement curved sound walls in 1972.  

They do make great shells.  Refer to the works of Felix Candela and Nervi.

At one time, ferro cement boats were the rage on the West Coast; almost
indestructible!

Lots of ferro cement boats were built in New Zealand also.

Neil Moore, S.E.


At 01:14 PM 09/04/1999 -0400, Mark Gilligan wrote:
>Walter
>
>I believe that if you will read ACI 549 you will find that ferrocemento is
>a real option.  
>
>According to ACI 549 "Ferrocemento is a type of thin wall reinforced
>concrete commonly constructed of hydraulic cement mortar reinforced with
>closely spaced layers of continuous and relatively small wire diameter
>mesh.  The mesh may be made of metalic or other suitable materials"
>
>The mortar can be applied by hand or by shotcreting.  As such you would not
>necessarily need forms and segregation would not be a problem.  The hand
>appliction seems ideal for people building their own homes.
>
>This process is often used on shell structures and with the right curvature
>can allow very thin concrete sections thus reducing the amount of concrete
>needed.
>
>Mark Gilligan
>
>**************************
>>Michael
>
>That's a good point, but as I said in a previous post, houses are intended
>to be built by the owner, so if we make walls thinner we are going to have
>a segregation problem in the bottom part of the wall since it's height is
>7.5 feet. We don't have ferrocement here in Peru, and we are trying to use
>easy to get materials so the houses can be built all over the country.
>
>
>
>At 04:33 PM 03/09/1999 -0500, you wrote:
>>Walter;
>>
>>I'm probable off base but you may want to look into Ferrocement and the
>>experience various workers there have amassed.  There has been a good
>amount
>>of Italian and Mexican (and even some North American!) work I believe and
>>the ACI (committee 549 - I think) even has a publication on it.  In your
>>case the value maybe in thinning up the section (i.e.. less mass) with the
>>same amount of cement and giving it some shape (scary thing shape).
>>
>>cmd
>>
>>----- Original Message -----
>>From: Walter Sheen Paoli <wsp(--nospam--at)dhl.com.pe>
>>To: <seaint(--nospam--at)seaint.org>
>>Sent: Friday, 03 September, 1999 11:27 AM
>>Subject: Minimum Temperature Reinforcement
>>
>>
>>> Dear Fellows:
>>>
>>> We have been working developing a small house for poor people. This one
>is
>>> made out of four inch reinforced concrete walls. We have been able to
>>prove
>>> that a 1400 psi concrete is enough for the expected lateral forces and
>>also
>>> for dead and live load. We have used the minimum specified steel
>>> reinforcement for temperature and tested a natural scale module in a
>>> laboratory. We have found that it resists 8 times the expected lateral
>>> force. Now since we made the cement contents as low as we could, now we
>>> want (if possible) to put less steel reinforcement. Now I'd like to ask:
>>>
>>> 1.- Temperatures between summer and winter have a 25 Celsius degrees,
>>which
>>> is not a lot. How is this minimum steel reinforcement determined ?
>>> 2.- In your opinion, for cracking control, would it be bad to use less
>>steel?
>>> 3.- We are planning to use welded wire reinforcement. If we specify
>small
>>> distance between wires, would it be possible to use less amount of steel
>?
>>>
>>> Thanks for your help.
>>>
>>>
>>>
>>>
>>> Walter E. Sheen
>>> Civil Engineer
>>> Paseo de la Republica 6403. Lima 04
>>> (511) 446-6237 (511) 446-9407
>>> Lima, Peru<
>
>
>