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  1. JR55

    Doweling Pier Footing Into Slab

    I'm evaluating a pier and spread footing design and the original designer is using hooked dowels from the wall into the slab. I see the logic in using the dowels to reduce the shear load and the overturning moment to the foundation, but can't find anything to quantify the contribution and can't...
  2. JR55

    High strength bolts for corrosive environment

    I'm looking to specify high strength bolts (nominal tensile strength = 150 ksi) which would be Group C bolts per ACI 360 Table J3.2. We are going to use them in a corrosive environment for a salt storage shed, which appears to be excluded per AISC J3.1. Is there a bolt available that maintains...
  3. JR55

    NBCC ULS Overturning Factor of Safety

    We are reviewing a design for a foundation designed to Canadian NBCC. My coworker wants to equate ULS building reactions to strength design and design the foundation with a factor of safety of 1.0. Since I'm used to seeing ASD reactions used with a factor of safety of 1.5, I'm wondering if...
  4. JR55

    Soil Weight for Footing Bearing & Overturning

    So it sounds like for bearing checks it would be reasonable to use: e =(Mr-Mo)/P where Mr includes the existing overburden, but the P has the existing overburden subtracted out.
  5. JR55

    Soil Weight for Footing Bearing & Overturning

    Vertical reaction (P) plus weight of concrete, soil if considered, and stored bulk material (W)
  6. JR55

    Soil Weight for Footing Bearing & Overturning

    Not quite, I understand that any existing soil should be neglected in terms of the weight, but I’m wondering if the same weight would still contribute to the resisting moment when calculating the eccentricity in the bearing stress equation?
  7. JR55

    Soil Weight for Footing Bearing & Overturning

    As far as I understand, the weight of the soil above the footing is included in the footing overturning and sliding calculations, and neglected in the bearing calculations when a net allowable bearing pressure is given. When calculating the bearing stress, (P+W)/B[1+6e/B], the soil weight...
  8. JR55

    Coulomb's Earth Pressure Slope Backfill Ka Height

    Does it make a difference if the footing is buried under a floor surface? This seems to indicate that if the backfill is not directly on the footing then the height should be taken as the height of the...
  9. JR55

    Coulomb's Earth Pressure Slope Backfill Ka Height

    I'm looking at a retaining wall with straight sides and sloped backfill. I've seen the answer alluded to on a couple of posts, but want to confirm. For sloped backfill considering stability, is the height to be considered the height to the wedge at the edge of the footing? Or is it the same as...
  10. JR55

    Pinned Base Assumption - Model vs Anchors

    That's what I figured. And because it's mostly judgement, I'm assuming there's no direct references allowing this? I am getting some push back where someone wants to apply moment to all W section connections independent of base plate thickness, which seems needlessly overcomplicated at best.
  11. JR55

    Pinned Base Assumption - Model vs Anchors

    I know the fixity of the column base plate has been discussed extensively, and that the pinned or fixed assumption in the model is not fully representative of what is practically occurring as there is no 100% pinned or 100% fixed connection. However, I am wondering if there is any direct...
  12. JR55

    Hydrostatic Pressure on Drilled Shafts

    The geotechnical report for the drilled shafts (approx 3'-6" dia) I'm working on says to add hydrostatic pressure when below the groundwater table. I'm hoping for guidance on how this load should be applied. As far as I understand, the 62.4 pcf value should be multiplied by the depth of the pier...
  13. JR55

    Anchor Shear Reinforcement for Anchors in Wall

    One question I think I know the answer to - If the U-bar encompasses the edge reinforcement bar (typically assumed to have 3" clear cover), this would make the clear cover of the U-bar less than 3". Assuming it is cast against earth, is there any way to get around this rather than moving all of...
  14. JR55

    Spread Footing with Trench to Frost Depth?

    It sounds like the detail is constructable and a good option. I guess my only remaining question is then what would the pressure distribution look like? Can I assume it will be triangular and design it as I would for a uniform thickness? If not, are there any resources you could point to for...
  15. JR55

    Spread Footing with Trench to Frost Depth?

    The column is 3' diameter round and centered on the footing with loads around 300 ft*kips.
  16. JR55

    Spread Footing with Trench to Frost Depth?

    I am designing spread footing for a single column that will see relatively high moments at the base. The client wants the footing to start at grade, and so we're left trying to meet frost depth. My thought would be to use an approximately 42" thick footing and put enough steel top and bottom...
  17. JR55

    Anchor Shear Reinforcement for Anchors in Wall

    Thanks you all. KootK, for the downward opening U-bars, to me this sounds similar to what is detailed for tension reinforcement in Figure R17.5.2.1a. Can the same U-bar be considered to contribute to tension breakout in the vertical leg and shear breakout in the horizontal element?
  18. JR55

    Anchor Shear Reinforcement for Anchors in Wall

    I'm attempting to clarify the shear anchor reinforcing in ACI 318-19 section 17.5.2.1 for anchors into the top of a 16" wide wall. Because of the width of the wall, I don't have room to develop hairpin bars, so I am wondering if stirrups are the only option as the hook and lap would take care of...
  19. JR55

    Even Poured Wall Height to T.O Ftg?

    I recently had someone bring up that they typically detail continuous poured walls with an even dimension (whole feet) from top of wall to top of footing. I've always detailed using a 12" thick footing for small structures and used the wall height below grade to achieve frost depth (for example...
  20. JR55

    Headed Bars for Anchor Tension Reinforcement?

    I am designing anchors that see tension, and in an attempt to preclude side face blowout, we want to shorten the anchor embedment length as much as possible (for limited edge distances). Because ACI 17.5.2.1 states the reinforcement must develop on each side of the breakout surface, I initially...

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