We were recently asked the question, “What Do Most Engineers Use for Masonry Design: ASD or SD?” and we asked the opinion of Richard Bennett, Professor of Civil and Environmental Engineering at the University of Tennessee, Chair of MSJC Main Committee. Here is what he said:

When I have taken informal polls at a few recent seminars, about 80% design with Allowable Stress Design (ASD). However, it seems that we are gradually switching to Strength Design (SD). In my masonry class, I teach SD, and then spend about 2 days on ASD. The way I see it, the advantages to SD are that it is similar to concrete design, and for some cases, such as when the allowable masonry stress controls the design and for shear walls, SD can provide a savings in reinforcement. The two disadvantages to strength design that I see are:

1. A second-order analysis has to be done for all walls, no matter how short and stout. This is becoming less of an issue with more and more use of software. The software does not care to do extra work.

2. There are some walls you cannot build due to the maximum reinforcement requirements. This is what causes people to switch to ASD. It is a bit crazy, as the purpose of the maximum reinforcement requirements is to limit reinforcement to provide ductility. So when designers cannot make the wall work due to the maximum reinforcement requirements, they switch to ASD, which requires even more reinforcement. I don’t have a strong opinion, but would suggest strength design.

We also thought we would take a look at the sales figures for our ASD CodeMaster and our SD CodeMaster to see which one was more popular. The ASD CodeMaster is more popular with the split in sales being 66% ASD CodeMasters versus 34% SD CodeMasters.