Beams cracking torsion

[Ahmad Alhamad]

Hello,

I want to ask about cracking torsion when the member subjected to high axial force like tempreture
then the term under the square root will be minus, so then what is this mean ?
can i ignore torsion or the cracking torsion will be zero ?

 

[dik]

Not familiar with ACI to any extent... if tension, is Nu +ve or -ve?

Dik

 

[Ahmad Alhamad]

Nu is negative for tension

 

[rapt]

Axial tension reduces torsion capacity. You cannot ignore it.

Your cracking torsion is 0 if the section is already cracked in tension!

 

[Ahmad Alhamad]

even beam is cracked why cracking torsion should be 0 ?
if the beam works compatible, the code allowed to reduce Tu to Tcr
so then if Tcr is zero should i design for full Tu even if it works compatible ??

 

[rapt]

If the section is already cracked, the concrete provides no torsional strength. Reinforcement has to be supplied for the total.