Min. reinforcing requirement in CMU wall? 2

[engr567]

Is there a minimum reinforcing requirement for interior non load bearing CMU Walls? If yes, is there a section in BLDG code that refers to the min. reinforcing requirement? I would appreciate your input.

 

[JAE]

No minimum reinforcement - but under the IBC you have to have a wall strength to resist 5 psf lateral force. That sometimes kicks you from having an unreinforced wall to having a slightly reinforced wall. Depends on the height of wall and the f'm (which in the US is usually 1500 psi.)

 

[msquared48]

On page 285 of Amrhein, 3rd edition, it is mentioned in note #2 at the bottom of the table that the primary reinforcing minimum is .0013bt, and the transverse minimum is .0007bt, where "t" is the effective thickness. This is old (1978), but a starting point.

I will have to look further for the current IBC reference.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[msquared48]

Designing where I live, the Pacific Northwest, and seeing what I have over the years, I would never design an unreinforced CMU wall, partition or otherwise, in spite of the code allowances. Too much can and does happen, especially considering remodels, and #3 or #4 reinforcing is cheap.

Peace of mind is a good thing.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[slickdeals]

Talking about Amrhein, I can't seem to find a used book for less than @120. Any pointers? It seems like that book is heading in the direction of becoming a collector's item.

We are Virginia Tech
Go HOKIES

 

[engr567]

Thank you all.

 

[DHKpeWI]

Are you using the walls to resist lateral loads? In that case there are minimum reinforcing requirements depending on the "R" value you intend to use to determine your seismic base shear.

 

[msquared48]

Slick:

Mine is NOT for sale.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[concretemasonry]

Jim Amrhein passed away a few years after we worked on ACI 530.

He was legend in masonry design. The only knock possible on his book is that he was on the payroll of a group in a seismic area and the content was on that. Despite that his book is still worth over $120 (if it is for sale) because of the insight behind the words.

On of his philosophies is that if you know the contractors ability, the main thing is if the wall is plumb, straight, and has full mortar joints and is made from the block of the right strength it should exceed the structural requirements. He hated prescriptive codes and clean-outs since they created discontinuities in the wall and in the construction process. He also disliked reinforcing walls for no real reason, which is contrary to many engineers opinions.

After the Northridge earthquakes, he could immediately spot the reason for the failure and often pointed out the over-reinforced areas that changed the character and stiffness of the structure and concentrated loads.

Dick

Engineer and international traveler interested in construction techniques, problems and proper design.

 

[iceberg187]

The latest version of the Amrhein book: Reinforced Masonry Engineering Handbook, 6th Edition can be purchased directly from MIA for $100. This edition was updated for ACI 530-05:

http://www.masonryinstitute.org/book.php?catID=5&pID=146

 

[slickdeals]

Thanks for the link, I ordered the book. Looking forward to going through it.

We are Virginia Tech
Go HOKIES