Silos Design Limits

 

I have spent my entire professional career – now approaching 43 years – at Jenike & Johanson. Working with clients to solve or prevent problems involving the storage, flow and processing of bulk solids has been both challenging and professionally rewarding.

One topic that has been of particular interest to me over the years is understanding the loads applied to the walls of silos and the ability of silos to resist those loads. Unfortunately, solids-induced loads are not easily determined or understood. As a result, silos fail with a frequency that is much higher than almost any other industrial structure.

Perhaps the first attempt to calculate pressures on silo walls was published in 1895 by the German engineer Janssen. Starting about 50 years ago, various groups around the world have made attempts to codify material-induced silo wall pressures, and that process continues today.

The most modern and complete silo design code in use today was adopted by the European Committee for Standardization (CEN) in 2005. The formal designation for the English version of this code is British Standard BS EN 1991-4:2006 “Eurocode 1 – Actions on structures – Part 4: Silos and Tanks”. Other codes in common use include ACI 313-97 “Standard practice for design and construction of concrete silos and stacking tubes for storing granular materials” and ANSI/ASAE EP433 “Loads exerted by free-flowing grain on bins”.

All codes have limits of application, but most engineers are unaware of how many common silo design conditions are not covered by any code.  For example, no code provides a method to calculate hopper wall pressures for a conical hopper in which the cone angle changes from top to bottom. Also, no code provides calculations for loads acting on silo internals, such as so-called Chinese hat inserts or cross beams.

I am in the process of writing a technical paper describing these limitations in detail. If you’d like a copy when it’s finished, please let me know.

 

 

11 Responses to Silos Design Limits

  1. Yes, I would like to have a copy of your report on handling of bulk material in silos. Regards.

  2. Massimiliano Zampa says:

    John, Could you send copy of the paper to me? Thanks

  3. Hi John

    I would like a copy too please

    Thanks. James

  4. Paul Janze says:

    John,
    We have been working with J&J on the wood pellet silos for the Atikokan Biomass Conversion project and well recognize the limitations of the current codes. I would be very interested in receiving a copy of your paper.
    Paul Janze
    Ausenco Engineering

  5. Hi John,
    Could you please send a copy of your paper to me also, please?
    Thanks,
    Joseph

  6. David Jones says:

    Hello John,

    J&J have been most helpful and insightful in the past.
    Would certainly appreciate a copy of the report if it is still available.

    Kind regards
    David

  7. Hello John

    I would like a copy of your paper.

    Thank you

    Gary Blenkhorn
    Bulk Handling Technology Inc.

  8. Gopakumar.P says:

    Hi John,
    I would like to have a copy of the paper
    you may send to my email.
    Regards,
    Gopakumar.P

  9. Nene Gaio says:

    Please send me a copy of your paper
    thank you

  10. Chris Geijs says:

    John, please send me a copy.
    Best regards,
    Chris