I'm sure earlier ACI versions also have the same criteria as my own local code (NZS3101:2006) is predominantly based on ACI318-02 from 15+ years ago and it has an almost identical criteria for this situation? Isn't this in part what the requirements in ACI318-14 in 23.5 are for? It gives rules for reinforcement requirements for the 'spreading' of bottle shaped struts that don't cross perpendicular/parallel to reinforcement? This in turn allows for a better βs factor. HELP! I'd like your help with a thread that I was forced to move to the business issues section where it will surely be seen by next to nobody that matters to me: RE: Walking Column - Strut Capacity Agent666 (Structural) 14 Aug 19 22:05 That compression will dissipate into the body of the wallumn over a finite distance which is really just what the model reflects. After all, much compression will enter the system from the vertical steel in the columns above and below. In a way, it might actually be argued that this model does actually do a better job of capturing elastic stress distributions. That said, it does a much better job of jiving with conventional reinforcing schemes. It is true that it is not the most direct load path and, perhaps, not the model most congruent with anticipated elastic stresses. On occasion, I've used the strategy shown below. This may not be a big deal but it's not something that's captured in our conventional STM's. That may complicate detailing.ī) The bar compression in the verticals will need to walk laterally. Some things that worry me:Ī) At the nodes on either end of the strut, you'll need to get the bar compression quickly, and convincingly, into the nodes. That said, I've seen no formal recommendation on what that inclination might be.Ģ) I'd be very careful with the "close enough" strategy. RE: Walking Column - Strut Capacity KootK (Structural) 14 Aug 19 18:00ġ) Practically, there must be some "close enough" inclination. What does the forum think on this "close enough" idea? Maybe other codes have weighed in on this? Otherwise you'd have to resort to inclined reinforcement which looks odd to me and seems unnecessary. This kills me if all my steel is vertical and horizontal and actually results in having less compressive capacity in the transition column as in the top column.Ģ) It appears to me like there should be an angle of strut inclination that should be "close enough" to parallel so that I don't have to disregard my vertical steel (maybe less than 10 degrees?). Here is where I would like to see the forum's opinions:ġ) Per ACI, I can't consider longitudinal reinforcement that isn't parallel with the strut axis in the strut capacity. I want to reinforce the walked column conventionally with vertical steel and horizontal ties. I am considering the strut in the transition column to be bottle-shaped and, per ACI, I would use a βs factor of 0.6 (without special transverse reinforcement) or 0.75 (with special transverse reinforcement). I'm thinking of doing a strut and tie check in addition to some other checks and I am struggling with the strut capacity calculation. I am in the United States so ACI 318 prevails. Consider the top, transition and bottom columns to all be the same thickness into the page. I have a column that the architect would like to walk over.
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