## Overturning Moment & Stabilizing Moment

Structural Layout Vignette and Multiple Choice

### Overturning Moment & Stabilizing Moment

Can someone walk me through the steps of figuring out question #28 in the NCARB Exam Guide: http://www.ncarb.org/ARE/~/media/Files/ ... _Guide.pdf (see link for diagram)

What is the factor of safety against overturning for the concrete shear wall shown if resisted only by gravity forces? Assume the weight of concrete equals 150 lb/ft3, and the dead load equals 240 kips. Ignore the weight of the soil over the footing.

Thank you!
lilly9

Posts: 59
Joined: Sun Feb 01, 2015 10:30 am

### Re: Overturning Moment & Stabilizing Moment

Have you tried looking at Mikes notes for the NCARB exam guide?
mono

Posts: 56
Joined: Sun Sep 07, 2014 1:59 pm

### Re: Overturning Moment & Stabilizing Moment

Thanks for the help -- I get it now!
lilly9

Posts: 59
Joined: Sun Feb 01, 2015 10:30 am

### Re: Overturning Moment & Stabilizing Moment

I have this same question. How do you do it? Or where are Mike's notes as referenced above?
ballet3gal

Posts: 1
Joined: Mon Apr 10, 2017 2:35 pm

### Re: Overturning Moment & Stabilizing Moment

ballet3gal wrote:I have this same question. How do you do it? Or where are Mike's notes as referenced above?

viewtopic.php?f=8&t=1171

Coach

Posts: 12499
Joined: Wed May 23, 2012 2:08 am

### Re: Overturning Moment & Stabilizing Moment

ballet3gal wrote:I have this same question. How do you do it? Or where are Mike's notes as referenced above?

Find total dead load moment about the lower right corner. Find the overturning moment. Divide DL moment by overturning moment.

[((((16*40*1.5)+(20*6*2))*150)/1000)+240]*10 = 4200'k
24*42 = 1008'k
4200/1008 = 4.17

Coach

Posts: 12499
Joined: Wed May 23, 2012 2:08 am

### Re: Overturning Moment & Stabilizing Moment

How do you find the #10 in this equation?

[((((16*40*1.5)+(20*6*2))*150)/1000)+240]*10 = 4200'k
24*42 = 1008'k
4200/1008 = 4.17

Thanks!
Femmemirage

Posts: 1
Joined: Sat Dec 17, 2016 12:50 pm

### Re: Overturning Moment & Stabilizing Moment

Femmemirage wrote:How do you find the #10 in this equation?

[((((16*40*1.5)+(20*6*2))*150)/1000)+240]*10 = 4200'k
24*42 = 1008'k
4200/1008 = 4.17

Thanks!

It's the moment arm for the dead load.

Coach