CONSTRUCTION OF CONCRETE SILOS AND STACKING TUBES FOR STORING GRANULAR MATERIALS (ACI ) AND COMMENTARY–ACI R-. ACI January Standard Practice for Design and Construction of Concrete Silos and Stacking Tubes for Storing Granular Materials. Does anyone have experience with ACI and designing steel bins? I am specifically concerned with calculating loads on bins and the.
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Register now while it’s still free! Close this window and log in. Are you an Engineering professional? By joining you are opting in to receive e-mail. Promoting, selling, recruiting, coursework and thesis posting is forbidden. Does anyone have experience with ACI and designing steel bins? I am specifically concerned with calculating loads on bins and the use of the overpressure factor in section 4.
This section specifies the overpressure factor to be a minimum of 1.
An older version of the spec ACI had factors up to 2. It seems to me that many bins have been sucessfully designed in the past just using filling pressures per the Janssen equation, but on the other hand, published literature does clearly indicate that pressures during emptying are greater. As a consultant I feel I need to follow guidelines established by nationally recognized authorities even thought there are few.
I am doing an investigation now and will begin writing a program to do these calcs when I can determine the best way to proceed. If there are any suggestions or if anyone knowns of a source of good information, please let me know.
Any help will be appreciated. Buzek as the author. I think I saw this years ago and it was a good reference.
It’s one of the books I had forgotten about, or at least couldn’t remember enough to be able to find it again. Thanks for the help. I have used ACI quite a bit.
I think they difference is the horizontal pressure coeficients. Gaylord, and I believe the 3113-97 ACI calculated the lateral pressures based on active pressures xci the charted overpressure coeficients.
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ACI utilizes at rest pressures larger. I pretty axi use the at rest pressure with the 1. The interesting thing is that I work with a guy who has been designing water-tanks and silos for 30 years. He uses the Gaylord’s infomation. Unwillingness to change what has worked forever.
My designs 33-97 always either comparable or slightly conservative to him. I can live with that. When I first saw the 77 spec I was not comfortable with increasing the designs by a factor of 2. It’s possible that many of the ‘old’ designs exist with a reduced factor of safety.
Thanks for your comments. Very true about the older designs. When I get into other types of bins I like to have testing done to verify the lateral pressures. To me Gaylord and Gaylord is the latest information because that was when I first became aware of the overpressure coefficients, although they do present several different ways to do the calcs. I like the ACI method because it is a published 313–97 instead of a bunch of research papers. Prior to that the people Aaci knew were using equations published by Ketchum about a hundred years ago based on Janssen’s work.
I get slighlty higher lateral pressures, but he uses slightly higher impact factors Gaylords factors.
It seems to work out fairly close. His arguement is that he is confortable with his designs based on his experience and therefore sees no reason to utilize a seemingly more conservative approach. I think I’m with you on this in terms of the K factor and overpressure of 1.
I get the impression when reading the Gaylord text that the value of K is sometimes used as a fudge factor to skew results towards where the researchers want to end up 3313-97. But that’s just a guess. What I want is ‘good’ final answer.
While I find the science interesting, where I end up 31-397 more important than how I get there. What I recall from using the Gaylord book is that they give several different equations and factors, and then say “You can use this one, but some people use this one and this third method seems to work okay too”.
The point to be learned is that there is not just a wide variation in the methods used, but in the loads themselves.
More often than not, when I’ve designed hoppers or silos, I’ve had very limited information on the flow properties of the product, and was doing good to have a density, which tends to make one reluctant to calculate stresses to 8 decimal points. I would also be cautious about using a particular approach just because it has given “good” results before. The structure got built, it didn’t fall down, but does anyone really know how safe it is?
You could go on for years building structures that were seriously overstressed, until finally one collapses. It looks to me at this point that I will be using a combination of methods depending on if it’s a shallow bunker or deep bin, filling or emptying, funnel-flow or mass-flow, or a vertical wall or hopper. Based on test results shown in Gaylord the ACI equations are as good as any and it is an actual written specification. For hoppers both the Jenike and Walker equations are probably satisfactory.
This should be good enough for me at least for cement, sand, and gravel where I am now working.
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There are many other materials that can cause unusual and serious functional and loading problems, so I agree that caution is certainly warranted when designing a bin. I’ve come to the conclusion that many of the homemade bins and the bins produced by small inexperienced fab shops have less than the desired factor of safety. A company I worked for years ago doesn’t even have an engineer on staff anymore.
You can make more money that way. For those so inclined the Jenike and Johanson site at www. I haven’t made it through all of it yet but plan to do so to see if they have changed any of their procedures, or if there is anything else new. Thanks for the input, -Mike. Red Flag This Post Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework. Digital Transformation may be defined in a number of different ways by analysts or enterprise software vendors.
Defense manufacturing is all about project manufacturing and project accounting. Students Click Here Join Us! Posting Guidelines Promoting, selling, recruiting, coursework and thesis posting is forbidden. Bin design with ACI Very true about the older designs. Bin design with ACI aggman, You mention that you work with someone who has been doing this for years that uses Gaylords information and is unwilling to change.
Bin design with ACI What I recall from using the Gaylord book is that they give several different equations and factors, and then say “You can use this one, but some people use this one and this third method seems to work okay too”. Bin design with ACI It looks to me at this point that I will be using a combination of methods depending on if it’s a shallow bunker or deep bin, filling or emptying, funnel-flow or mass-flow, or a vertical wall or hopper. Resources Digital Transformation may be defined in a number of different ways by analysts or enterprise software vendors.
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