Torsion of continuous beam 1

[dccd]

Say that I have a 2 span of continuous beam subjected to torsion, is the torsion value smaller than those 2 single span beam subjected to torsion of same value ??

I think the torsion of continuous beam shall be lower, correct me if I am wrong...

Anyone can correct and explain the situation???

 

[BAretired]

Weird enough, when I assign all support to become pinned, the torsion increase noticably, why ? Shouldnt the torsion value decrease ? Because the support is unable to take torsion, so tosion shall decrease, right ??

Wrong! That would make the structure unstable. You may be entering the wrong information into your software. Either that or you are not using suitable software to consider torsion. Even without torsion, you cannot make all supports pinned if you expect to get the correct results.



BA

 

[dccd]

Yes, i know , I am just trying to see the difference between pinned and fixed condition...

Well , here's another situation , I have a 2 span curve beam subjceted to UDL , torsion is caused by the curve beam subjected to UDL, (previously all we discussed is 2 span staright beams, with UDL is eccentric to the center of beam)..

Here's the torsion diagram look like , the torsion is somewhat higher at the part which has higher curvature... Previously the torsion value is highest at the support , now for curve beam , torsion is higher at midspan,I am confused now.

Can you help to explain this ?

 

[BAretired]

You cannot use a pinned condition. Your software should reject it as being unstable.

I can't find your diagram for the curved beam.

BA

 

[dccd]

Edited with diagram, you can see that the torsion value is the highest somewhere near support , but not excatly at the support for curve beam...

Whereas for straight beam, the torsion value is the highest at support , why ?

 

[BAretired]

Whereas for straight beam, the torsion value is the highest at support , why ?

I have no idea why that would be. In fact, I am very suspicious that the result is wrong. Is the beam uniformly loaded along a circular arc?


BA

 

[dccd]

Is the beam uniformly loaded along a circular arc

Yes, it's. The UDL is all along the circular arc beam...