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RE: USACE TI 809-04 Seismic Design for Buildings

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From: rlewis(--nospam--at) [mailto:rlewis(--nospam--at)]
Subject: Re: USACE TI 809-04 Seismic Design for Buildings

I wonder if someone could explain the type of military documents that are
available.  Specifically, what is the difference between the TM and TI
documents.  I am starting to get quite a collection of NAVFAC documents and
they seem to be all related, just different numbers and letters.


I've been working for the Corps for about 5 years and I still don't have the
document naming convention understood.  There are TM's, TI's, EM's, and
ETL's just to name a few.  These 4 types are the only ones that I have
worked with as a structural engineer.  The differences between each type is
subtle.  I don't know the history of their development, but here are my
observations that might be helpful.

TM:  Technical Manual or "Tri-Service Manual"  These are the engineering
manuals that are quite common in most offices that do military work.  They
usually have a gold cover.  Its called a tri-service manual because the
Army, Navy, and Air Force all use the same document.  Each agency calls it a
different title.  For example, Army TM 5-809-3, Navy NAVFAC DM-2.9, and Air
Force AFM 88-3 all refer to the same manual "Masonry Structural Design for
Bldgs".  So if you are downloading this publication from the Corps of
Engineer's website, you'll have to look it up as an Army TM since the Corps
is an agency under the Army.  As I understand it, TM's will no longer be
published (electronically or paper), and they will eventually be replaced by
the TI's.  TM's cover a wide variety of subjects, and they are intended to
be used for military projects only, although many engineers use them for
civil projects (flood protection) as well.

TI:  Technical Instructions.  These documents are fairly new and they are
only distributed by electronic media (internet).  The TI's are starting to
replace the TM's as new TI's are created.  The intent of the TI's is to
provide a document which will get periodically reviewed and updated.  If a
user produces any hard copies from the electronic format, they should
periodically check the hard copy against the electronic version prior to use
to assure that the latest instructions are used.   For a quick introduction
to TI's, download TI-800-01 "Design Criteria".  This TI has a list of other
TI's which will be eventually phased in.

EM:  Engineering Manual.  Basically, this is the same thing as a TM.  EM's
cover a wide variety of subjects, and they are generally used for civil
projects more than military projects.    

ETL:  Engineering Technical Letter.  Each letter covers a specific subject.
I believe the letters were developed because the subject of the letter is
too specific to incorporate into an existing TM, TI, or EM.  Also, EM's and
TM's take a lot of time to get revised and redistributed.  The ETL's can act
as appendices, revisions, or clarifications to the existing EM's and TM's.

Everything mentioned above is available for public download at
If you are in doubt to which reference you are supposed to use, you should
consult the Corps district you are doing the work for. 

John Connor
Kansas City, MO