Which dimensions of columns supporting flat slabs do not require a punching shear check (according to ACI code)?

  • 1
    $\begingroup$ There is no dimension for which punching shear does not need to be checked. It always must be checked. It will depend on the column shape, column location, slab thickness, applied loads, concrete shear strength, reinforcement, etc. $\endgroup$ – atom44 Mar 30 '17 at 17:38
  • $\begingroup$ So why does nobody check punshing shear for a shear wall? (for example 0.6 m x 2.4 m) and in Softwares like SAFE it doesn't show the punshing shear ratio as it shows for columns ? $\endgroup$ – J.Daou Mar 30 '17 at 18:26
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    $\begingroup$ Well people do check for punching shear for such a wall (at least they should). This the responsibility of the engineer. You can't rely on software to do your thinking for you. If as the engineer you feel punching shear is a potential failure mechanism then it should be checked. I worked on a project where 1.2m x 0.3m 'columns' required punching shear reinforcement. Experience may tell you that punching shear is not a likely issue in some situations, that is different than not needing to check. $\endgroup$ – atom44 Mar 31 '17 at 10:11
  • $\begingroup$ Can you provide an example on how to check punching shear of a column on a slab ? or any link or book would be suffice. $\endgroup$ – J.Daou Mar 31 '17 at 17:37
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    $\begingroup$ Although it is for Eurocodes this website is a good place to start. I would imagine most/all concrete design textbooks would deal with this, but I'm not familiar with ones dealing with the ACI code. $\endgroup$ – atom44 Apr 1 '17 at 12:20

As has been mentioned in the comments, there is no specific combination of dimensions that mean that punching shear is not a problem. An Engineer may make a judgement that a check isn't required based on experience, but a check would always be the safe option.

ACI (American Concrete Institute) even has a similar question in its Frequently Asked Questions: Punching shear check for shear wall foundations


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