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  • Users: ajh1
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  1. ajh1

    AISC's Reduced Allowables for High b/t ratios

    In AISC 360-16 Section E7 would be applicable for compression loading while Sections F3 through F5 would be applicable for flexure depending upon which elements are deemed slender.
  2. ajh1

    Design of Cold Formed Girt Systems

    Extra fasteners are not for the panel, but to make the girt check and use the AISI factors based on the 12" fastener spacing. The full width spacing fails the 12" check so you can't use that provisions and thus you need to design with strapping, bracing, etc. to get the unbraced lengths of the...
  3. ajh1

    Design of Cold Formed Girt Systems

    For insulated panels we have used a rivet connection that would swedge out inside of the panel on centers closer than the width of the panel as needed. Typically for the US that would only be at the corner wind zones. We have deemed that the insulated panel viewed as a whole would meet the 12"...
  4. ajh1

    safety factors for loads

    Safety factors cover several individual items. You seem to be primarily interested in the safety factor on the load itself. That is best described as the load factor inherent for each load type in an LRFD/LSD type load combination. For LRFD/LSD, the resistance factor (0.65 - 0.95 typically)...
  5. ajh1

    2-150 Ton OH Crane Supporting Structure

    Second the idea about using fixed base conditions, otherwise if you need any real tolerance on side movement, i.e., things like stacker cranes, you will never get there. If you interconnect the crane column to the main column in a rigid fashion (effectively make it a single deep column) then...
  6. ajh1

    Design of Cold Formed Girt Systems

    One of the other challenges when looking at IMP explosive conditions is that the typical cold-form girt is not a doubly symmetrical member and thus takes a bit of a hit in the explosion equations because it is more subject to rotation of the member. They can be used for low level explosions...
  7. ajh1

    Design of Cold Formed Girt Systems

    Normal design practice following AISI is to allow the wall panel to brace the outer flange of the girt. This is assuming that the panel has sufficient strength, is connected reasonably directly to the flange (no 4" of rigid insulation in between panel and girt for example), and has some level...
  8. ajh1

    Bolt Threads in a Shear Plane

    In a tapped bolted joint I believe you will always have threads in the shear plane. If you stop the threads below the shear plane (assuming the bolt head is at the top), then the shank of the bolt is in the shear plane (which is good), however you can't thread a shank into a hole that is...
  9. ajh1

    Butler "Foundation design and construction manual" 1984

    I had an email from the head of Butler R&D this afternoon. They are no longer going to respond to distribution requests as they are concerned regarding the age of the document and the likelihood that there are provisions in it that are potentially in conflict with current code and design...
  10. ajh1

    Butler "Foundation design and construction manual" 1984

    As KootK indicated, I've been providing that PDF file to a number of people over the years. However, I retired at the end of 2018 and no longer have a copy on my files. I suggest contacting rkPeck at the usual Butler email address and he should be able to get you a copy. I've alerted him via...
  11. ajh1

    Allowable strength/stress design

    generally speaking you should always be using the latest edition of the standard. There were a number of issues with the older allowable stress design as that standard was not kept up to date for many years until the introduction of the first ASD/LRFD AISC standards. That said, the real...
  12. ajh1

    Building/runway impacts for overhead cranes.

    A lot of this is based on the travel speed of a crane. If a crane is pendant operated or hand-geared it can only travel as fast as the operator can walk under it. Thus the impact forces are lower as there is less dynamic action. With a cab controlled or remote controlled crane, the crane...
  13. ajh1

    Estimating Bolt Torque from Snug Tight Specification

    The snug-tight definition has bounced around for a few years, but the most current is the "full effort of an ironworker" version. The first one cited above would be fine for a condition that was intended to simply be snug-tight, but was found to be in conflict with the turn-of-nut guidelines...
  14. ajh1

    Welded Z purlin overlapped splice

    It could be done, but welding 0.063" (1.6 mm) thickness is tricky. Special weld procedures required so that you don't burn through the material you are trying to weld. Welding code would be AWS D1.3 in the US. A lot of the PEMB attractiveness is there is rarely any on-site welding required.
  15. ajh1

    Purlin design: Failing under slenderness ratio

    Ron247, the details you provided above are from Butler. The small angles were replaced a number of years ago by a 5" deep channel that braces both flanges at the same time. The channels have tabs that project through those same holes in the purlin web and have a drop pin that connects one...
  16. ajh1

    ASCE 7 Wind Enclosure Classification Question

    With the exception of Partially Enclosed, I would say that the other conditions all would need to be the same for all directions. Open is defined as all walls more than 80% open. Enclosed is now something like no more than 4 sq. ft. of opening. Not sure how either of those could be construed...
  17. ajh1

    Unbalanced Snow Load on Hip-Gable-Hip Roof

    You might consider the provisions that were in the old UBC 97 code. I think that is the most recent US code that really went into a snow buildup due to intersecting roofs like you have. As I recall those provisions didn't apply until the roof pitch was at least 2:12.
  18. ajh1

    1.25" hole in existing metal building frame column and portal column

    Some of this is a function of how high up the building column and portal column you are at. Most portals on metal buildings tend to be fixed knee and pinned base (as opposed to a wind post that is a fixed base), so a hole near the floor is going to have minimal moment in the portal frame column...
  19. ajh1

    Upward roof length for leeward drift?

    US rules are generally perpendicular to the canopy wall as JAE noted. Canadian rules look at both dimensions of the upper roof and calculate an adjusted length as a result. Not sure there is an angle result directly related to that. Be sure to include not just the immediate upper surface but...
  20. ajh1

    Shear tearout of bolt in structural standards (AS4100)

    There is some current research ongoing in the cold-formed steel arena looking at this issue. One of the big questions that is intended to be addressed is that there appear to be two distinct forms of the failure depending upon I suspect the ratio of the width of the plate vs. the distance from...

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