Moment capacity of shear wall?

[drile007]

I have rectangular shear wall with mesh reinforcement in the web and concentraded reinforcement at the both ends of the wall. Is there a simple equation to calculate moment capacity of the wall and which include contribution of mesh reinforcement.


Drile007

 

[Lion06]

My McCormac text has an equation for the moment capacity of a shearwall with uniform reinforcement. I guess you could do your own strain analysis (since you don't really have uniform reinforcement). The first question I would ask is if that mesh extends into the footing. If it does not, then you can't use it in your shearwall moment calcs. Additionally, I think you are only allowed to use it in the moment capacity calcs if your Vu<phiVc. if 0.5phiVc<Vu<phiVc, you must provide minimum shear reinforcing, but it can still be added into the moment capacity. If Vu>phiVc, you can't add it into the moment capacity. Also, make sure this isn't required for out-of-plane loads before you start using it for the in-plane loads.

 

[DaveAtkins]

I would design it like a rectangular beam, and ignore the mesh reinforcement.

DaveAtkins

 

[drile007]

Hi,

Dave: I think that neglecting uniform reinforcement is too conservative (once I did the exact calculation and I got difference by approx. factor 2).

StructuralEIT: could you send me a scaned page of the McCormac text.

Thank you



Drile007

 

[Lion06]

drile007-
I would need an email address, but post it at your own risk (it is frowned upon in the forum). I don't know how to post a picture. Also, how will the mesh be anchored to the foundation? Is the mesh needed for shear?

 

[drile007]

StructualEIT:

You are right, I won't play with the forum... Can you write the formula on the forum. I'll be very happy if you try to describe the quantities. Can you also write me exact title of the McCormac book and the year of publish (maybe I'll find it in our library).

Thank you




Drile007

 

[Lion06]

0.5(As)(fy)(lw)[1+Pu/((As)(fy))][1-c/(lw)]
?=(As)(fy)/[(f'c)(lw)(t)]
?=Pu/[(f'c)(lw)(t)]
c/lw=(?+?)/[2(?) + ?(sub1)*(Beta1)]

This is actually on page 987 of my MACGREGOR text, not McCormac, sorry about that. It is the 4th edition Reinforced Concrete Mechanics and Design.

 

[Lion06]

hmmmmm.. it changed the symbols I copied from word into question marks. I wonder why that is. I will address shortly, I am busy right now.

 

[UcfSE]

The number of the book is ISBN 0-13-142994-9. You should be able to find it at a major online book store such as Amazon.

There are some rules associated with the applicability of the equation you are discussing (it is empirical). Make sure you check that you can use this.

 

[WpgKarl]

Check out the following resource:

Reinforced Concrete Design - A Practical Approach by Svetlana Brzev and John Pao printed in 2006. - you should be able to find the book on Amazon.com

See Chapter 13.6 Shear Walls - Section 13.6.4 - Design of Flexural Shear Walls. They give a method for calculating the capacity of a flexural shearwall with distributed vertical reinforcing.

Note - Book is based on the new 2004 Cdn code, but you could use the same concepts for ACI code.

 

[drile007]

Thank you guys for your valuable posts.

Drile007