# Masonry Wall



## MOOK (Oct 13, 2009)

1- In SEAOC/ ICC book V.2 page 218

Design Example 4- Masonry Shear Wall Building

Why load combination 2 was used instead of load combination 3

1.2D + 0.5Lr (Load Comb. 2)

1.2D + 1.6Lr (Load Comb. 3)

Load Comb. 3 will provide larger load than load 2.

Any reason for that?

2- Can we increase the allowable stresses in masonry when using ASD load combinations or only when using the Alternative load combinations??

Thanks


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## DAVE9999 (Oct 14, 2009)

MOOK said:


> 1- In SEAOC/ ICC book V.2 page 218Design Example 4- Masonry Shear Wall Building
> 
> Why load combination 2 was used instead of load combination 3
> 
> ...


what book is this? (SEAOC/ ICC book V.2)


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## kevo_55 (Oct 14, 2009)

Dave,

Here's a link to that book: http://www.iccsafe.org/e/prodshow.html?pro...BjhjZkbfw1429|7

The image is wrong though. The image displayed is for the "volume 1" book.

I hope this helps!


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## DAVE9999 (Oct 14, 2009)

kevo_55 said:


> Dave,
> Here's a link to that book: http://www.iccsafe.org/e/prodshow.html?pro...BjhjZkbfw1429|7
> 
> The image is wrong though. The image displayed is for the "volume 1" book.
> ...


I don't have that one, do you think it is necessary for the test? :burgerking:


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## kevo_55 (Oct 14, 2009)

Dave,

To be honest, if you are taking any exam next week then I wouldn't bother getting this book.

If you are taking the SE2 or SE3 (CA/WA) in something like 6 months to a year then I would.

Any other exams other than these would help but may be a bit overkill.

I hope this helps.


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## MOOK (Oct 14, 2009)

kevo_55 said:


> Dave,
> To be honest, if you are taking any exam next week then I wouldn't bother getting this book.
> 
> If you are taking the SE2 or SE3 (CA/WA) in something like 6 months to a year then I would.
> ...


Any thoughts about my questions Kevo55


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## MOOK (Oct 14, 2009)

kevo_55 said:


> Dave,
> To be honest, if you are taking any exam next week then I wouldn't bother getting this book.
> 
> If you are taking the SE2 or SE3 (CA/WA) in something like 6 months to a year then I would.
> ...


Dave

If you are taking SE-I, you won't need this book.


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## kevo_55 (Oct 15, 2009)

Mook,

My SEAOC books are at home. I'll try to crack open my volume 2 tonight and help you out.


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## teda (Oct 15, 2009)

Mook, for your question 2:

Under IBC2006, you can not use stress increase for Masonry.

Under ACI530, you can.

If both codes list in the question, IBC2006 will govern. This means you can not use stress increase.

That is my understanding to code.



MOOK said:


> 1- In SEAOC/ ICC book V.2 page 218Design Example 4- Masonry Shear Wall Building
> 
> Why load combination 2 was used instead of load combination 3
> 
> ...


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## kevo_55 (Oct 15, 2009)

MOOK said:


> 1- In SEAOC/ ICC book V.2 page 218Design Example 4- Masonry Shear Wall Building
> 
> Why load combination 2 was used instead of load combination 3
> 
> ...


Mook,

What specific page are you looking at? Is it the out of vertical loading on page 215? I guess that I am not seeing load case 2 being used anywhere.

Also with respect to the stress increase. During the actual exam you will not be asked to do this. In practice you can do this but it will no longer help (as much). Please look at the "w" in those load cases. Most likely you will have to use a w=1.3 for your wind loading. If you do this, you will cancel out all of the "help" that you got in your allowable stress increase. Seismic will not be effected by this so technically you still can use a stress increase for those alt. load combos.

Either way, technically you still can for seismic but you will never will be asked this during an exam. This is a practice issue only.

I'm a bit conservative as a practicing engineer anyways. I have never used an allowable stress increase.

I hope this helps!


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## MOOK (Oct 15, 2009)

kevo_55 said:


> Mook,
> What specific page are you looking at? Is it the out of vertical loading on page 215? I guess that I am not seeing load case 2 being used anywhere.
> 
> Also with respect to the stress increase. During the actual exam you will not be asked to do this. In practice you can do this but it will no longer help (as much). Please look at the "w" in those load cases. Most likely you will have to use a w=1.3 for your wind loading. If you do this, you will cancel out all of the "help" that you got in your allowable stress increase. Seismic will not be effected by this so technically you still can use a stress increase for those alt. load combos.
> ...


Thanks Kevo for your help

For Question #1:

Actually it is not about stress increase. In volume 2 page 218 on the top of the page.

The solution suggested "LRFD" Load comb 2 and load comb 5. They did not use load comb.2 because load comb.5 governs. However, if we use "LRFD" load comb. 3 (1.2D + 1.6Lr) it will govern over load comb.2 and load comb.5 eventhough there is no seismic force included in it.

I wonder why they did not use it !!!!!!!!!!!

For Question #2:

I was just double checking to know if ASD load combinations would allow for stress increase or not but as far as I know the alternate load combinations in IBC allow for stress increase.


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## kevo_55 (Oct 18, 2009)

Mook,

For the masonry wall, the out of plane seismic forces will control the design. The worst case load combo with the out of plane seismic load would be the 1.2D+0.5LLr+E load case. The solution is only calculating the axial portion of the load case on the top of page 218.

For your item #2, you are correct.


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## MOOK (Oct 18, 2009)

kevo_55 said:


> Mook,
> For the masonry wall, the out of plane seismic forces will control the design. The worst case load combo with the out of plane seismic load would be the 1.2D+0.5LLr+E load case. The solution is only calculating the axial portion of the load case on the top of page 218.
> 
> For your item #2, you are correct.


This makes sense Kevo. What made me confused that they wrote Comb. 2 and Comb.5 in misleading way.

Thanks alot for your help.


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## kevo_55 (Oct 19, 2009)

No problem!!


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