NASCC Technical Highlight #1: “Steel Specifications Unraveled” Presented by Jon Beier

Let’s start with what even are specifications.  When you are designing any structure, you will perform calculations (both by hand and with the help of computer simulation).  If the structure is to be constructed, you will then prepare construction drawings that reflect the member sizes and configurations, connection details, and any other information necessary for the contractor to understand your design intent.  The cover page of your plans will contain some “General Notes”, which may contain such information as material properties used, applicable codes including year of code, the loading assumptions, etc. (years later people will likely want to know these design values and procedures).  Then, in many cases you will also submit an 8 ½” x 11” packet of additional text information that goes into depth regarding the procedures and material you want the contractor to use.  Specifications typically follow a defined format in which each typical topic has a designated number and generic wording that you as the engineer may adjust.

For steel structures, some of the important specifications include:

·      Steel shapes used on the job and the corresponding materials (e.g. bolts, rolled shapes, decks)

·      Testing, protection, and/or repair procedures

·      Statement of whether an AISC certified fabricator is required

·      Finishes (e.g. fireproofing, primer, or none) and surface preparation (hand tool prepared, power tool prepared, or more expensive preparations)

·      Design Methodology used (ASD vs LRFD), deflection limits, and camber

·      Deck profile and number of spans, i.e. the number of spans over which a single continuous piece of decking will extend (typically 1 or 2), minimum unshored length, i.e. each decking has a maximum value of span for which you can use it without supporting it during construction; this specifies the minimum of that maximum value, and minimum yield strength of decking material.

Much of this information may already be on the plans (either in the General Notes or the drawings themselves, so you can simply refer to the plans, e.g. “Deck profile as shown on plans”.  It is highly recommended not to show information in two places because as information changes, you may change it in one location and not remember to change it in the other location (or not even remember that its stated in another location).  This applies in general to your entire design.  Redundant statement of information can lead to construction problems, which can add cost to the job, or result in an unsafe structure if uncaught.  Another important point is that if you are reusing revised versions of Specifications from another job, be sure to meticulously read them to ensure all relevant information is updated and any irrelevant information is deleted. Okay, so let’s say you do have duplicate information in the plans and the specification that is contradictory.  Which applies?  Technically the plans govern over the specifications, but in the interest of avoiding finger pointing (and potentially law suits), it’s recommended to have a clause in your specifications and plans that indicate that when a conflict occurs, the stricter of the two clauses applies.

And lastly, why have General notes at all?  Why not have all the information contained in the Specifications.  Well, general notes are a part of the building plans, which typically will be held by the building owner for many years.  Whereas oftentimes, specifications are discarded following completion of construction.