Effective Date of Rule: July 1, 2007.
Purpose: To amend the 2006 International Building Code (IBC), chapter 51-50 WAC related to structural design and the use of ASCE 7, Minimum Design Loads for Buildings and Other Structures, published by the American Society of Civil Engineers.
Statutory Authority for Adoption: RCW 19.27.074 and 19.27.020.
Other Authority: Chapters 19.27 and 34.05 RCW.
Under RCW 34.05.350 the agency for good cause finds that immediate adoption, amendment, or repeal of a rule is necessary for the preservation of the public health, safety, or general welfare, and that observing the time requirements of notice and opportunity to comment upon adoption of a permanent rule would be contrary to the public interest.
Reasons for this Finding: The state building code council (council), based on the following good cause, finds that an emergency affecting the general welfare of the state of Washington exists. The council further finds that immediate amendment of a certain council rule is necessary for the public welfare and that observing the time requirements of notice and opportunity to comment would be contrary to the public interest.
The declaration of emergency affecting the general welfare of the state of Washington is based on the following findings:
The council's adoption of chapter 51-50 WAC, the 2006 edition of the IBC, published by the IBC, will take effect July 1, 2007. After adoption of this code document, it was found that there was a significant technical error in one of the referenced documents used to calculate structural seismic design loads. The referenced standard is currently going through the process of making the correction. In the interim, the council determined that it was necessary to make these technical corrections to the 2006 IBC. Immediate adoption of this amendment is necessary so that structural engineers will have proper guidance for determining earthquake loads in building design.
The council concluded that it is in the best interest of the general safety and welfare of the state of Washington to amend the provisions related to ASCE 7-05 concerning seismic design loads and include these amendments as WAC 51-50-1613.
Number of Sections Adopted in Order to Comply with Federal Statute: New 0, Amended 0, Repealed 0; Federal Rules or Standards: New 0, Amended 0, Repealed 0; or Recently Enacted State Statutes: New 0, Amended 0, Repealed 0.
Number of Sections Adopted at Request of a Nongovernmental Entity: New 1, Amended 0, Repealed 0.
Number of Sections Adopted on the Agency's Own Initiative: New 0, Amended 0, Repealed 0.
Number of Sections Adopted in Order to Clarify, Streamline, or Reform Agency Procedures: New 0, Amended 0, Repealed 0.
Number of Sections Adopted Using Negotiated Rule Making: New 0, Amended 0, Repealed 0; Pilot Rule Making: New 0, Amended 0, Repealed 0; or Other Alternative Rule Making: New 1, Amended 0, Repealed 0.
Date Adopted: June 8, 2007.
John P. Neff
WAC 51-50-1613 Section 1613 -- Earthquake loads.
1613.7 Modification of ASCE 7. ASCE 7-05 including Supplement #1 is modified according to this section.
1613.7.1 The following equations found in Section 12.8 and Section 15.4 expressing limitations for the seismic response coefficient Cs shall be defined as follows:
|Equation 12.8-5||Cs = 0.044SDSI≥0.01|
|Equation 15.4-1||Cs = 0.044SDSI≥0.03|
|Equation 15.4-3||Cs = 0.044SDSI≥0.01|