T-Beam Fixity single span 1

[BatMan]

Random question, but if a single span T-beam is casted in place, wouldn't this likely be detailed as fixed? Unlike precast girders, isn't it typical practice to develope top steel for cast in place beams or is it not always the case?Thank you for input.

 

[KootK]

f a single span T-beam is casted in place, wouldn't this likely be detailed as fixed?

In CIP concrete it would typically be detailed to have some nominal negative moment capacity near the supports in acknowledgement of the fact that there's always some restraint in CIP construction. Often you'll see this as detailed such that you'll have 1/4 to 1/3 of the mid-span positive moment capacity available as negative capacity at the ends.. And the bars will typically extend into the beam 0.25 - 0.30 L. Through interactions here, I've learned the the Euro-codes actually have provisions for this which I think is pretty nifty.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[JAE]

In addition to KootK's comments - realize that the amount of "fixity" is only dependent on the stiffness of the thing fixed to.
If you have thin little columns, or a slender wall that you are supported on, there isn't much stiffness there when compared with a large column or mass of concrete.

So the correct answer is...it depends.

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