Masonry Wall

[MOOK]

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

 

[DAVE9999]

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

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

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

 

[kevo_55]

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!

 

[DAVE9999]

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!

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

 

[kevo_55]

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.

 

[MOOK]

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.

Any thoughts about my questions Kevo55

 

[MOOK]

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.

Dave

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

 

[kevo_55]

Mook,

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

 

[teda]

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.

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

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

 

[kevo_55]

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

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

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!

 

[MOOK]

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!

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.

 

[kevo_55]

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.

 

[MOOK]

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.

 

[kevo_55]

No problem!!