Masonry: ASD or LRFD

[NC Structural Engineer]

I am taking the SE exam in October, and I just finished the PPI practice exam this weekend. The problems regarding masonry in most cases stated to only use ASD for the solution.

To this point, my understanding is that on the exam I should be able to solve the problems in ASD or LRFD based on my preference. Will the actual SE exam require the use of ASD on most masonry problems (with the exception of slender walls)? Or will I be able to choose?

Thanks

 

[Andy Lin]

In most cases, you should be able to choose if I recall correctly... (except for AASHTO questions which are always LRFD).

 

[smahurin]

Yes you can choose.  The multiple choice answers give an LRFD and an ASD answer.  IE:

A) 25kips (ASD)/ 32kips (LRFD)

B) 12kips (ASD)/17kips (LRFD)

etc...

 

[TehMightyEngineer]

Yep, a lot of the PPI materials erroneously carried over the previous exam specification requirements that slender walls be solved using LRFD requirements and others solved using ASD requirements. In the actual exam I suspect little to no problems outside of concrete and AASHTO will specify which method to use.

In my opinion I'd use ASD for all masonry, cold-formed, and wood. I'd use LRFD for steel, concrete, AASHTO. I'd also use LRFD for any general load questions involving ASCE 7-10.

 

[NC Structural Engineer]

Thanks for the responses. Thats what I thought, I wanted to make sure since I have learned masonry for the exam, and chose to learn LRFD since its basically the same as concrete design.

 

[TehMightyEngineer]

Yeah, that's the best reason to use LRFD for the exam; I still highly recommend you do walls with out of plane loads under ASD, though. There are no requirements to consider 2nd order effects with ASD and this avoids the iterative nature of LRFD regarding walls with out of plane loads.