Masonry 4

[MMN54321]

I am new to masonry design and need a check list for residential
Some complete design examples would be great

What I am unsure about is irregularity how do you model odd shapes,

 

[JedClampett]

Buy a textbook. Amrhein's "Reinforced Masonry Engineering Handbook" is good, albeit out of date.

 

[sandman21]

Dont think 2015 IBS is out of date.

Reinforced Masonry Engineering Handbook, 8th Edition

 

[MMN54321]

Yeah
I have text books and know how to do most design
What Iam looking for is a good check list for residential
And a work flow that fits residential with some design examples

 

[masonrygeek]

There aren't many publications that are exactly what you are looking for. Here is one that then has links to specific subjects:

https://ncma.org/resource/concrete-masonry-residential-details/.

 

[MMN54321]

In TMS 402 it states that the maximum useable strain is to be 0.0025 for concrete masonry.
But it dose not say anything about the steel strain.
Can you please explain how to calculate it.

 

[driftLimiter]

TMS 402 Section 9.3.2 a) Strain compatibility exists between the reinforcement, grout and masonry.

Typically the assumption is that plane sections remain plane. Proportioning beams for flexure is iterative just like concrete design. Assume steel yields check strain in CMU etc. This is pretty fundamental to CMU design.

If your looking for a checklist specific to masonry for residential construction I might suggest building it up yourself.

Generally things to consider are Vertical loads, Main Lateral System Loads, Anchorage and attachment details, serviceability (control joints).

 

[MMN54321]

How do you calculate how the change in length of the steel when it yields. TMS 402
says that the usable strain in the masonry is 0.0025.
So what would the usable strain in the steel be?
They are using 0.00207 in all of the examples.
I don't understand where they are getting this number.

 

[driftLimiter]

It comes from hooke's law for tension? This is fundamental first principles stuff.

 

[MMN54321]

Hook law only works in the elastic region, if we are assuming the steel yields there must be some other assumption.

 

[driftLimiter]

The design method when you have a tension controlled section is to analyze the strain at the initiation of the yielding. Post-elastic behavior is not explicitly addressed in Conc/CMU design.

 

[MMN54321]

I found how they get the 0.0027 in the examples, I had to go my concrete design book.
It lays it out right (No long drawn out explanation about hooks law either.)
Just divide the grade of the steel by E.

 

[driftLimiter]

:facepalm:

It lays it out right (No long drawn out explanation about hooks law either.)
Just divide the grade of the steel by E.

What is hookes law? STRAIN * E = STRESS ----> i.e. -----> Strain = Stress / E ... Come on man this is like First year engineering. No drawn out explanations.

I am sorry but if you are bothered by the fundamentals then perhaps you aught to consider another trade.

 

[MMN54321]

Its funny how every time you answer someone you have to insult them.
I have noticed that all your answers always have a condescending tone.
Why? people just want help not to be insulted

 

[driftLimiter]

I offered multiple responses to the original post that offered help and guidance to solve your problem. Sorry I didn't just provide the answer without drawn out explanations. And your right I think its even fair to say that my last post was just full on condescending not just condescending tone. But from your replies to me its almost like you don't care what the fundamentals are you just want to know the answer and that bothers me. Please continue to endeavor to learn and expand your knowledge don't let an old grump like me slow you down.

 

[JoshPlumSE]

I'll 2nd JedClampet's recommendation of Amrhein's "Reinforced Masonry Engineering Handbook". That is the best masonry book I have seen. It is a bit out of date, but it's still a very good place to start to understand the basics of masonry design.

Some other recommendations:
Obviously, you need to buy the code TMS 402 / ACI 530.
I use Taly's "Design of Reinforced Masonry Structures". But, I don't "enjoy" it as much as Amrein's book.
Honestly, I feel like there is important stuff in the 1997 UBC for Masonry design that I can't find very many other places.

Some basic thoughts:
There are two methods of design for masonry. Allowable Stress Design and Strength Design.
I believe you'll find the Strength Design provisions to be very similar to the concrete design methods (ACI 318). There are little differences here and there, but the concepts are the same.

Allowable Stress design of masonry, however, is really different. I don't find it very intuitive. It's like a bunch of engineers got together in a room and pulled numbers out of their heads.... "this is the allowable for shear". "This is the allowable for flexure". In many ways, it's more straight forward to use. But, the "first principles" are a little weird. Also, I find that the TMS / ACI codes don't provide everything you need to do allowable stress. That's why Amrein's book is so good. Lots of additional tables and equations that help. I

 

[MMN54321]

Well thank you for your help, I just have a lot of material to get through

 

[MMN54321]

Josh

I have and I am reading TMS 402/606-16 Building Code Requirements and Specification for Masonry Structures.
I have the Strength Design of Masonry, and yes I much prefer Strength Design over ASD.
I am going to buy the books you suggest today, I didn't know they existed.

 

[MMN54321]

This is off subject but, how do you calculate the tributary area of a slab on a masonry stem wall?
Most of it is sitting on dirt