Who Cares About Wind?

摘要

With the long overdue adoption of the IBC 2006, California engineers are beginning to learn new code provisions in preparation for taking the giant step from the 1997 UBC to the new standards. Among changes in Chapter 16, most members will find in the adopted code that they are referred to, a complex chapter on wind design in Chapter 7 of ASCE 7-05. Except for low-rise light-framed buildings, lateral force design of most structures tend to be controlled by seismic forces in California and other high seismic zones. While a simplified procedure in ASCE 7 may be used for low-rise buildings sixty feet or lower in height, the procedure includes various limitations such as no unusual geometrical irregularity. The complexity of the detailed Analytical Procedure has haunted even the most experienced engineers. At the request of SEAOC President Norm Scheel, the reactivated Building Code Committee started a Wind Ad Hoc Committee. The assignment for this Ad Hoc committee is to work in conjunction with the reinstituted Tri-state (California, Oregon and Washington) Wind Committee to develop an alternative design procedure that would simplify the current wind provisions in ASCE 7. The Tri-State Wind Committee met in February of this year. Based on two days of intensive discussions, the group developed a draft document on alternate design procedures for all height buildings. The Ad Hoc committee plans to recruit volunteers for case studies to ensure workable steps prior to submitting the draft document to ICC and ASCE 7. The Tri-State Wind Committee, in concert with NCSEA GES, plans to submit a code change proposal, consisting of the alternative wind design procedure, to ICC for adoption into the 2009 IBC. The Tri-state Wind Committee also plans to submit a similar code change proposal to ASCE for adoption in the next ASCE 7 Standard. The purpose of this paper is to highlight the proposed alternate design procedure. Comparative examples will be presented to demonstrate the use of ASCE 7 procedures and the proposed alternate method. The need for a simplified wind design for IBC has been echoed in the western states and throughout most of the United States. We hope that efforts such as this will inspire more SEAOC engineers to b become active in the process involving the code development in IBC as well as on committees for industry consensus standards that are referenced in the IBC.