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  1. Splitrings

    Horizontal bridging in pre-engineered wood trusses (residential)

    An engineering firm here in VT was found liable last year when a roof collapse happened during construction. A number of workers were injured. The collapse was due to insufficient bracing. The EOR was inexperienced, according to the media report.
  2. Splitrings

    Detention Tank Design

    Can the lid be used to provide top support to the walls? This way they act more like a simply supported member rather than a cantilever? The top would have to be installed before backfilling.
  3. Splitrings

    PCA Method - Slab on grade for multiple storage tanks

    The document you refer to has a short section on uniform loading of slabs on grade. The tables that are shown actually come from the PCA document "Slab Thickness Design for Industrial Concrete Floors on Grade". This document has more supporting info including design equations.
  4. Splitrings

    Horizontal bridging in pre-engineered wood trusses (residential)

    All three planes; bottom chord, web and top chord planes, need to be laterally and diagonally braced. As mentioned above, BCSI Handbook explains it all.
  5. Splitrings

    Existing Lumber Safety Factor

    Take a look at ASTM D245.
  6. Splitrings

    Active earth pressure and sliding of a buried structure

    The SCS Technical Release #74 uses a wall thickness to height ratio as a guide as to whether the wall is flexible enough for active pressures to develop. It states a ratio of t/H<= 0.085 is flexible enough for Ka values to be used. This TR references a paper by Karl Terzaghi. This same TR...
  7. Splitrings

    Engineering Post Frame Buildings

    You show a pinned condition at nodes N9 and N10 of your RISA model. If this represents your ground surface, it is likely much too stiff for soil backfill. If you had a slab on grade that was constraining your post, a pinned condition may be more realistic. If you have soil backfill, I would...
  8. Splitrings

    Engineering Post Frame Buildings

    My geotechnical expertise is pretty weak but I am guessing the skin friction between the full concrete collar and soil is insufficient to engage the available shear strength of the surrounding soil. I just looked at the new ASABE EP486-12 and it states a "device that enlarges the base" can use...
  9. Splitrings

    Engineering Post Frame Buildings

    Are you sure the PT post is HF? You sure it isn't SYP?
  10. Splitrings

    drain pipes embedded in mat foundations

    A welded HDPE pipe might be a good choice. Its flexible and you have no joints to leak.
  11. Splitrings

    Engineering Post Frame Buildings

    In IBC 2003 it is in a footnote to table 1804.2. In IBC 2012 it is in section 1806.1. These increases are only allowed for load combinations that include wind or earthquake loads.
  12. Splitrings

    Engineering Post Frame Buildings

    If you are looking at the embedded section of the pole, ASABE EP486 has the equations.
  13. Splitrings

    Engineering Post Frame Buildings

    A first order analysis is done as a portal frame. Two posts and a truss in between, with or without knee braces. A second order analysis can be done by moment distribution, stiffness method, etc.
  14. Splitrings

    Snow Load Increase

    I suppose the AHJ could step outside the standard codes, but I can't imagine they would want to. If the GSL is 40 psf, the roof load for a cold, flat non slippery surface with an importance factor greater than 1 would be much greater than 40 psf. Maybe their intent was to specify a minimum...
  15. Splitrings

    Engineering Post Frame Buildings

    I guessing that most "pole structures" are not designed with diaphragms.
  16. Splitrings

    Snow Load Increase

    It must be a misprint. It would have to be specified as a GSL. The roof load is dependent on the characteristics of the structure.
  17. Splitrings

    Engineering Post Frame Buildings

    There are many different PT treatments and treatment levels. Some treatments have a long history of proven performance and others are questionable at best. Typically an oil borne treatment, such as Copper Naphthenate and Creosote, provide better long term performance. CCA is a water borne...
  18. Splitrings

    Engineering Post Frame Buildings

    A professor at Cornell University did some research on the diaphragm action from light gauge sheet metal siding and roofing. I am not sure if he published the research.
  19. Splitrings

    Engineering Post Frame Buildings

    ASABE EP486 will answer all your post questions. A post would be considered constrained at the ground surface if a concrete slab or other means was present. A post with a full collar acts just like a post without a collar, except it is much wider, therefore reducing the lateral stress on the...
  20. Splitrings

    How to model frictional resistance using FEM Software

    I just noticed you were trying to model a shear key. That will be a bit more difficult to model correctly. You won't develop full passive resistance until some displacement occurs. The friction between the rest of the footing and soil will develop just as displacement occurs. I am sure someone...

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