Overview

Roger L. Brockenbrough, P.E.

President
R. L. Brockenbrough & Associates, Inc.
Pittsburgh, Pennsylvania

Buildings should be designed to meet the requirements of state or local building codes. For the design of the structural steel framework, most codes refer to the specifications of the American Institute of Steel Construction (AISC), One East Wacker Drive, Suite 700, Chicago, IL 60601-1802 (www.aisc.org).

In 2005 the AISC published a new document, "Specification for Structural Steel Buildings." Referred to herein as the AISC Specification, it is known as a unified specification because it combines allowable strength design (ASD) and load and resistance factor design (LRFD) in a single specification. This chapter provides a summary of the main provisions of the AISC Specification and insight for design application.

The AISC Specification now provides common requirements for nominal strength, such that the ASD and LRFD design methods now differ mainly in the alternative use of safety factors or load and resistance factors. Also included are design requirements for certain members that were previously addressed in separate documents, such as angle members and hollow structural sections (HSS). The AISC Specification applies to the design, fabrication, and erection of structural steel for buildings, as well as for other structures designed, fabricated, and erected in a manner similar to buildings, i.e., with building-like vertical and lateral load-resisting systems.

The design of structural steel in seismic zones should also comply with the AISC's "Seismic Provisions for Structural Steel Buildings" (2005). The seismic provisions apply when the seismic response modification...