SE Practice Exam Vertical Forces Breadth #26

[nicculusreadicculus]

May someone please help me find these equations that NCEES just magically pulled out of a hat? There is no reference to them anywhere in TMS402-16 or 22

 

[Rabbit12]

Find yourself a masonry textbook or design guide. Amrhein is really good. We still use an old version of his book in our office.

 

[Celt83]

They are geometric formulas

Here is a derivation for k:


If I recall correctly j is the moment arm between the steel reinf. and the center of the triangular compression block with d factored out.

 

[nicculusreadicculus]

They are geometric formulas

Here is a derivation for k:
View attachment 1479

If I recall correctly j is the moment arm between the steel reinf. and the center of the triangular compression block with d factored out.

This looks good, but where did you get the f_m and f_s equations from? Why is f_m a triangular block? I only took reinforced concrete design in school. I don't think many universities teach Masonry design anymore. I recall the Whitney stress block being a rectangle like you did for f_s

 

[YC611]

The PE handbook has a section that gives those formulas.

 

[lexpatrie]

Conversationally, I think LRFD uses a rectangular stress block, but ASD is legacy and uses triangular.

 

[nicculusreadicculus]

The PE handbook has a section that gives those formulas.

View attachment 1485

Where did you find this? I don't think NCEES provides a handbook for SE exam?

 

[YC611]

Conversationally, I think LRFD uses a rectangular stress block, but ASD is legacy and uses triangular.

I agree and I believe most still stick with ASD for masonry.

Below is the screenshot of the strength illustration from the PE handbook.

 

[nicculusreadicculus]

I am so confused as to what I should even be studying. The PE Civil: Structural Exam Specs has TMS402 listed, but the PE civil handbook only has steel and concrete design references??

Why do they have to group all the PE civils together?? that is so impractical and illogical for someone who wants to do the PE Civil: Structural instead of the PE Structural...Make them separate for crying out loud!

 

[nicculusreadicculus]

And the PE Structural Handbook only references Concrete and Masonry, but not Steel or wood? Am I missing something?

 

[canwesteng]

I'm just as confused as you as to what you should be studying. Are you studying for the SE or PE? The civil PE handbook is for the PE, and the structural handbook is for the SE.

 

[Celt83]

This looks good, but where did you get the f_m and f_s equations from? Why is f_m a triangular block? I only took reinforced concrete design in school. I don't think many universities teach Masonry design anymore. I recall the Whitney stress block being a rectangle like you did for f_s

The fm and fs formulas are from mechanics of materials in general form both formulas are My/I, n is included in the fs equation because you need to transform the steel to an equivalent area of masonry using the modular ratio process of determining the composite section properties and stresses are also from mechanics of materials.

The triangular stress block comes from the use of ASD which is based on an elastic stress distribution. TMS 402-16, 8.3.2