Page 103 - Forensic Structural Engineering Handbook

DESIGN CODES AND STANDARDS 2.9

Development of Seismic Regulations for New Buildings. These provisions are a direct descen-
dant of the Tentative Provisions for the Development of Seismic Regulations for Buildings,
developed by ATC under sponsorship of the National Science Foundation and the National
Bureau of Standards (now the National Institute for Standards and Technology).
The two most significant differences between the 1993 edition and prior editions are
that (1) the 1993 edition is based upon a strength level limit state rather than an equivalent
loading for use with allowable stress design, and (2) the 1993 edition contains a much larger
set of provisions that are not direct statements of loading. The intent is to provide a more
reliable and consistent level of seismic safety in new building construction. Further back-
ground and commentary provisions can be found in the following publications:
Part 2, Commentary, of the NEHRP Recommended Provisions for the Development of
Seismic Regulations for New Buildings, Building Seismic Safety Council, Federal
Emergency Management Agency, 1991 edition.
Recommended Lateral Force Requirements and Commentary, Seismology Committee,
Structural Engineers Association of California, 1990.

In preparing the seismic provisions in ASCE 7-05, the Seismic Task Committee of ASCE
7 established a “scope and format” subcommittee to review the layout and presentation of the
seismic provisions and to make recommendations to improve the clarity and use of the stan-
dard. As a result, the seismic provisions of ASCE 7-05 are presented in Chaps. 11 through 23
and Apps. 11A and 11B, as opposed to prior editions wherein the seismic provisions were
presented in a single section (Sec. 9). The provisions for buildings and nonbuilding structures
are now distinctly separate as are the provisions for nonstructural components. Less com-
monly used provisions, such as those for seismically isolated structures, have also been placed
in their own distinct section. In addition to reorganizing Section 9 of ASCE 7-02, technical
changes were also made to the requirements of the standard primarily based on the 2003 edi-
tion of the NEHRP Recommended Provisions for the Development of Seismic Regulations for
New Buildings and Other Structures. Where ASCE 7 revisions vary significantly from those
made to the NEHRP provisions, new commentary has generally been provided.

Model Codes
As noted earlier in this chapter, the 2000 International Building Code and the successive
2003 and 2006 editions of IBC have replaced the model codes promulgated by BOCA,
ICBO, and SBCC. This section has been preserved from the prior edition of the book and
provides background regarding IBC and the earlier model codes.
Uniform Building Code. The Uniform Building Code was first enacted by the International
Conference of Building Officials in 1927. Revised editions of this code have been published
since that time at approximate three-year intervals. New editions incorporate changes
approved since the last edition. The Uniform Building Code is designed to be compatible with
related publications to provide a complete set of documents for regulatory use.
The provisions of the 1994 edition of the Uniform Building Code were reformatted into
the common code format established by the Council of American Building Officials. The
new format establishes a common format of chapter designations for the three model build-
ing codes published in the United States. Apart from those changes approved by the con-
ference membership, this reformatting has not changed the technical content of the code.
Provisions of the Uniform Building Code and the UBC Standards have been divided into
a three-volume set. Volume 1 contains administrative, fire- and life-safety, and field inspec-
tion provisions. Chapters 1 through 15 and Chaps. 24 through 35 are printed in volume 1 in