moment of inertia and modulus of elasticity

[monchie]

Hello,

Reducing modulus of elasticity of concrete by 50%, is it equivalent to reduce moment of inertia(ie, shear wall) by 50%?

It arises in a situation, where a software, doesnt have the facility to implement in its analysis of building, of reducing its moment of inertia.

For example , shear wall, in this software, you cannot reduce the moment of inertia of the shear wall on its major axis(in-plane direction) but you can reduce its moment of inertia on its out-of plane direction(minor axis).

The only work around on this software is to reduced wall stiffness or reduced modulus of elasticity of concrete.

 

[KootK]

Reducing modulus of elasticity of concrete by 50%, is it equivalent to reduce moment of inertia(ie, shear wall) by 50%?

I think that would have the desired effect on flexural stiffness and may well be the way to go. Of course, you'll need to remain aware of any unintended consequences that may result from modifying E. It may also affect axial stiffness, shear modulus etc...

HELP! I'd like your help with a thread that I was forced to move to the business issues section where it will surely be seen by next to nobody that matters to me:

http://www.eng-tips.com/viewthread.cfm?qid=456235

 

[IDS]

Reducing the E value by 50% will also reduce the axial stiffness by 50%, but if the reduction is to account for flexural cracking of reinforced concrete, the cracked section will have a reduced axial stiffness, and the axial stiffness only has a small effect on the overall behaviour anyway.

Doug Jenkins
Interactive Design Services

http://newtonexcelbach.wordpress.com/

 

[monchie]

Thank you very much KootK/IDS for your insightful ideas!