Shear strength of RC

[seaw]

According to Modified Compressiong Field Theory , the shear capacity of RC. upon the cracked angle (theta) . So my question is how can I know the correct cracked angle?

 

[ishvaaag]

You can read about these things in

Prestressed COncrete
Collins & Mitchell
Response Publications.

It is usual to accept teta be 45 deg for RC and 30 deg for PC.

You have the sheet of free download ShearEHE.mcd at the Collaboratory for Mathcad 2000 pro where calculation of teta is detailed, and many other sheets delivering the shear strength of RC and PC beams by US codes.

 

[seaw]

Does it mean Prestressed Concrete Structures text book by Collins & Mitchell ? If yes , there is one PC beam example in chapter 7 it shown that the cracked angle vary along the beam. From text book it doesn't explain so much about how to obtain the angle , it just only refer to table 7.3 that is fix the pairs of angle, v/fc' and strain-x (epsilon-x in the text book) already. Please give me a suggestion on how can I choose the angle if I want to vary angle along the beam. Thank you very much.

 

[ishvaaag]

Give me one e-mail address and I will try to send you an office 97 or so readable file where you can see what is in the worksheet to this purpose.

The PC beam sheet design example varies it along the beam, for what I remember.

 

[seaw]

etong_23@hotmail.com
thank you very much.

 

[StructuralDzine]

I think the concrete will crack at right angles to the principal tensile stress, which is also parallel to the principal compression stress.

Generally in a beam the angle will be between 30 degrees at low shear and 45 degrees at shear close to capacity.

Chris Rohde
Editor, Structural D-zine

http://www.topica.com/lists/Structuraldzine