Specifications for Slip-Formed Concrete Silos 2

[Kman57]

We are in the process of writing a specification for design and construction of a slip-formed concrete silo. We are trying to find a standard or "go by" spec to help us, but have had no luck finding one so far. Any ideas of where we could find a detailed spec to consult?

 

[SlideRuleEra]

Many industrial silos and chimneys are jump formed instead of slip formed. You may want to allow either approach in your specification.

Here is the "Queensland (Australia) Formwork Code of Practice 2006". Chapter 8 has "Special Requirements For Slip Forms and Jump Forms"

http://www.dir.qld.gov.au/pdf/whs/formwork_code2006.pdf

Another approach would be to contact Pullman Power, they design / construct many of the larger silos and chimneys

http://www.structural.net/chimney/index.html

http://www.SlideRuleEra.net

 

[dik]

SRE... dunno where you find them... but that Queensland article is excellent...

Dik

 

[Lutfi]

SRE, great feed back! You get a star from me.

I like to add Hoffman to the list of contractors to contact. They slip formed two silos 50 foot in diameter each simultaneously in Port Canaveral. It took them virtually one solid week while they worked 24-7. They also used a slag mix since the plant owner is in the slag business. The silos are beautiful white color due to the presence of slag. The mix I believe was 50:50. The slip moved at a rate of one foot per hour. Here is a link to their web site:

http://hoffmanninc.com/

I like to add that slip forming or jump forming is ways and means. I am not sure why the designer should get involved in providing specifications. Does anyone agree with me?


Regards,
Lutfi

 

[SlideRuleEra]

Lutfi - Thanks for your compliment. I agree with you that slip forming and jump forming are ways and means, and as an Owner's Representative neither we nor our Engineer of Record interfere with a qualified Contractor's approach.

However we often have used "defensive" specification language, such as a brief description of slip & jump forming in the BID document for this type project. This is to give us a legitimate reason to reject a "rogue" proposal from a Contractor who wants to use our project as a test of his "new and improved" techniques. I have been surprised how often a "good reason" to reject a proposal is needed.

On the other hand, the specification language also needs to be "vague" enough to allow for the true innovations that come along from time to time.

Dik - Thanks for your comment, too. My wife says that I can find these out of the ordinary documents because "I think like and internet search engine" and the links just "turn up" when I go looking to see what is out there.

http://www.SlideRuleEra.net

 

[Lutfi]

SRE,

I am in agreement with you. Your elaboration expanded more on what I was trying to say. Additionally, I like to talk with slip form contractors and "pick their brains" prior to issuing the construction documents on most current trends and methods. We as designers must be knowledgeable in the process, standards and methods so that we can protect the owner’s and public interests.


Regards,
Lutfi