Flexural Resistance using Skewed Reinforcement 2

[Quade999]

Hi Everyone,

When using skewed reinforcing to calculate flexural capacity the codes don't really give a guideline about taking into effect the skew of bars.
I'm assuming you can look at the problem using basic Trigonometry in the example below. Would the assumption be correct that if I am looking at bending about the axis of the dashed line that my effective area of steel per foot about this axis would be As = (AREAbar*12in/6in)*cos(45)?

 

[r13]

Are you reinforcing a corner in a two way slab, or the plan is skewed to the global axes? Can you draw more details.

 

[Agent666]

Try lookup the 'wood armer' equations. They will allow you to relate bending about any plane to reinforcement at some angle to the critical actions.

Try this paper to give you some insight into the general problem.

If you had other reinforcement orthogonal to the skewed reinforcement in any alighment that isn't parallel to the plane you're bending about it also contributes to the strength (if you like you have both directions of reinforcement being "skewed" relative to your bending plane).

 

[dik]

and if you have the same reinforcing strength at right angles, the slab is isotropic and has the same moment resistance at any angle...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[Settingsun]

What you drew is correct, though it might be safer to use the cos-squared form as in the image below as that matches how the bar spacing is usually specified. There's also a little more to the calculation of whether the reinforcement is sufficient.

When using the method below, I take the sign of Mxy and Mxy* as whatever requires greater reinforcement to avoid having to keep track of that sign convention.