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  1. thoughtofthis

    Helical screw pile / grade beam foundation

    I was referring to the piles beneath the retaining walls between the columns. IBC 1810.2.2 "Deep foundation elements supporting walls shall be placed alternately in lines spaced not less than 1 foot (305 mm) apart and located symmetrically under the center of gravity of the wall load carried...
  2. thoughtofthis

    Helical screw pile / grade beam foundation

    Generally, equipment foundations are separate for a reason like vibration, settlement, etc. Connecting them may be problematic. Secondly, equipment gets replaced and new foundations will be poured. If the grade beam is a part of your lateral force resisting system, that will now include the...
  3. thoughtofthis

    Concrete Quality, Mixing and Placing

    I assume you mean ACI 318-14. The best source of that type of information is ACI 301.
  4. thoughtofthis

    Ice loads on exterior mechanical equipment

    Do you consider ice loads on large mechanical equipment like cooling towers? If so, how? ASCE 7 Ch 10 doesn't seem to address it very well. SPX has a white paper on icing, but doesn't indicate how to consider it.
  5. thoughtofthis

    Deflection Criteria for Industrial Utility Racks Supported from Roof of PEMB

    The L/135 mentioned above was just to provide a relative comparison to the L/240 deflection limits I'm used to seeing for girders/beams on utility racks. I did not mean to imply that there was a deflection limit for the combined system. However, I do think the total displacement of the system is...
  6. thoughtofthis

    Deflection Criteria for Industrial Utility Racks Supported from Roof of PEMB

    No it's not codified in the US. Also, industry organizations like PIP do not seem to address it directly.
  7. thoughtofthis

    Deflection Criteria for Industrial Utility Racks Supported from Roof of PEMB

    In my experience, utility racks are typically designed using a deflection ratio of L/240 for beams between supports using the collateral + operating load. This can vary based on what's being conveyed in the pipes and to address specific loading conditions (e.g. - if the pipe rack is outside, you...
  8. thoughtofthis

    Minimum Shear Reinforcement in Cantilever Retaining Wall Footings / Critical Section for Shear

    1) Historically, ACI has explicitly exempted footings from the minimum shear requirements. In ACI 318-14 the chapters were rearranged and minimum steel requirements were put into chapter 7 (one-way slabs) and 9 (beams). Foundations are in chapter 13. Foundations says to design one-way shallow...
  9. thoughtofthis

    Direct Ponding Analysis Using RISAfloor

    So ponding analysis is covered in AISC K2 and SJI has a direct ponding analysis tool, but there are limitations to both. For instance, they're only applicable to rectangular bays with evenly spaced framing. I understand that ponding stability is iterative for an exact solution, but why can't...
  10. thoughtofthis

    Remove/replace a portion of and existing SOG

    You would be doubling the voids in the slab. Also, there's some recommendations in ACI 302.1 that you would want to consider that may make it impractical.
  11. thoughtofthis

    Shear studs in masonry

    Thanks for your responses. ACI 530.1 allows for A307 Gr A bolts, and specifying S1 makes them weldable. So, an alternative to having the bolts stick through may be to just weld bolts to the bottom of a steel plate.
  12. thoughtofthis

    Shear studs in masonry

    I was looking at typical steel joist to masonry connection showing 2 shear studs welded to a bearing plate. ACI 530 doesn't allow studs per se, so I went in search of the ESR to see allowable values...there wasn't one. Concrete only. So is this configuration technically not allowed in masonry...
  13. thoughtofthis

    Point horizontal load in diaphragm due to roof top unit wind

    There is a large rooftop unit going on a building with a metal roof deck and steel joists. Wind has been considered for overturning loads on the joists. How do you account for the horizontal load from the wind into the diaphragm? Do you just include the horizontal load when your calculating the...
  14. thoughtofthis

    Infill rough openings at elevator

    I have a masonry elevator shaft, where the elevator manufacturer has requested that the rough opening be the full length of one shaft wall (~12ft). This is much wider than the finished door widths. How is the infill supposed to work? Dowel into the masonry above and below and fit the blocks in...
  15. thoughtofthis

    Torsion in Steel Beam

    This seems like a pretty common problem (i.e. - joist seats putting an eccentric load on a beam). Worst case, bearing length is 2.5 inches and the reaction is approximately 1.25 inches from edge of flange. There are a few options that I know of, but each has it's own issues. 1) require the...
  16. thoughtofthis

    Steel deck span condition

    Thanks for your responses. My experience has been very similar to KootK. I've never seen anyone specify a condition other than 3 span even when the number of supports don't add up. I guess the underlying question is why does that need to be on the drawings? My only reference is that span...
  17. thoughtofthis

    Steel deck span condition

    Steel roof and floor deck capacities are typically presented as a function of span condition. Most calculations I've seen assume a 3 span condition to get the most out of the deck; however, if you don't have supports in multiples of 4, wouldn't you be required to design some of the deck to a...
  18. thoughtofthis

    Partially grouted wall using stretcher blocks

    msquared48 - Thanks for the feedback. I'm sure we could provide designs that accommodate this issue...but I shouldn't have to assume it's going to be constructed wrong [smile] If I only need vertical bars at 32 in. o.c., I shouldn't get a fully grouted wall. concretemasonry - I provided a...
  19. thoughtofthis

    Partially grouted wall using stretcher blocks

    Weight is the main issue. Weight impacts seismic. At large openings, it may impact lintels, etc.
  20. thoughtofthis

    Partially grouted wall using stretcher blocks

    We've noticed that our partially grouted walls end up containing more grout than we would like. It looks like the stretcher block may be part of the issue. Issue #1: ACI 530.1 3.3B 3d says, "Vertical cells to be grouted are aligned and unobstructed openings for grout are provided in accordance...

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