8/12/2019 Aisc Code Steel Building and Bridge 74

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Code of Standard Practice for Steel Buildings and Bridges, March 18, 2005

AMERICAN INSTITUTE OF STEEL CONSTRUCTION

16.3-62

SECTION 10. ARCHITECTURALLY EXPOSED STRUCTURAL STEEL

10.1. General Requirements

When members are specifically designated as “Architecturally Exposed

Structural Steel” or “AESS” in the Contract Documents, the requirements in

Sections 1 through 9 shall apply as modified in Section 10. AESS members or

components shall be fabricated and erected with the care and dimensional

tolerances that are stipulated in Sections 10.2 through 10.4. The following

additional information shall be provided in the Contract Documents when AESS

is specified:

(a) Specific identification of members or components that are AESS;

(b) Fabrication and/or erection tolerances that are to be more restrictive than

 provided for in this Section, if any; and,(c) Requirements, if any, of a mock-up panel or components for inspection and

acceptance standards prior to the start of fabrication.

Commentary:

This Section of this Code defines additional requirements that apply only to

members that are specifically designated by the Contract Documents as

“Architecturally Exposed Structural Steel” (AESS). The rapidly increasing use

of exposed Structural Steel as a medium of architectural expression has given

rise to a demand for closer dimensional tolerances and smoother finished

surfaces than required for ordinary Structural Steel framing.This Section of this Code establishes standards for these requirements

that take into account both the desired finished appearance and the abilities of

the fabrication shop to produce the desired product. It should be pointed out that

the term “Architecturally Exposed Structural Steel” (AESS), as covered in this

Section, must be specified in the Contract Documents if the Fabricator is

required to meet the fabricating standards in this Section, and applies only to

that portion of the Structural Steel so identified.

AESS requirements usually involve significant cost in excess of that

for Structural Steel that is fabricated in the absence of an AESS requirement.Therefore, the designation AESS should be applied rationally, with visual

acceptance criteria that are appropriate for the distance at which the exposed

element will be viewed in the completed structure. In order to avoid

misunderstandings and to hold costs to a minimum, only those Structural Steel

surfaces and Connections that will remain exposed and subject to normal view

 by pedestrians or occupants of the completed structure should be designated as

AESS.

10.2. Fabrication

10.2.1. The permissible tolerances for out-of-square or out-of-parallel, depth, width and

symmetry of rolled shapes shall be as specified in ASTM A6/A6M. Unless