I actually did some FRP strengthening of concrete back in the day BEFORE 440.2 was available, when you had to use data and procedures provided by the system manufacturers. On one job, in fact, we actually enlisted the aid of Antonio Nanni, then at Missouri-Rolla, who is now the ACI President. Anyway, it was difficult to negotiate all the raw data and rather sketchy procedures. When 440.2 finally came out a few years later, I had moved on to other things and didn't really get much chance to work with it. But I assumed they had made great strides in standardizing and fully elucidating the procedures for FRP strengthening.

Fast forward to today, when we have the second or third edition of the reference, and I'm now delving into it in depth for the first time. And I must say, they don't make it easy. First and foremost, the vast array of parameter names is woefully inconsistent. Depending where in the document you look, you've got different symbols for the same thing, and sometimes more than just two.

I'll give one example:

I'm trying to follow the methodology in the Example for flexural strengthening of a prestress beam found in Section 16.5, and it uses y-sub-t for the distance from the top of the beam (the compression fiber) to the centroid. However, if you look in Section 2.1-Notations, y-sub-t is defined as "vertical coordinate within compression region measured from neutral axis position. It corresponds to transition strain εt′." Yet when you do a search for yt in the PDF document, nowhere is it used in the sense that Section 2.1 implies. There are lots and lots of other examples, some minor, some not so much. There are numerous typographical errors as well, a few of which are utterly confusing (such as the introduction of the symbol rho-sub-e in one equation in the example problem, which after a half-hour of diligent searching I finally discovered was supposed to be P-sub-e).

I don't know what's going on with that committee, but I certainly hope they can afford some better proofreaders the next time around, and that they go over Section 2.1 VERY thoroughly, making sure that every notation appearing there is used somewhere in the document, and in the sense intended.

"No one is completely useless. He can always serve as a bad example." --My Dad ca. 1975