Update on Existing Buildings
The Seismic Committee of the Structural Engineers Association of Utah has been working with the Uniform Building Code Commission and the Utah Seismic Safety Commission to address the hazards of existing buildings within our state. Over the last several years, we have tried to advocate the need for a uniform means to update and improve our older buildings against earthquakes. Some of that effort has been fruitful and we’d like to keep the Professional community aware of some upcoming changes.
Beginning January 1, 2002 the International Building Code (IBC) 2000 will be the base design and construction code for the state of Utah. In addition, the Utah Uniform Building Standard Rules will contain an amendment to section 1614.2 Change of Occupancy that modifies the requirements for seismic upgrading of buildings. This change states that occupant load increases of 100% or more in addition to any reclassification to a higher Seismic Use Group will now require buildings to undergo seismic strengthening. This was to recognize the primary intent of building codes, namely, to protect life. There are two exceptions that strive to make this provision workable. The first would exempt buildings if the occupant load increase is less than 25 persons for the same Seismic Use Group. The second recognizes the difficulties existing buildings would have in meeting seismic requirements for new buildings. It will now be permissible to show equivalent strength and safety or to use a nationally recognized standard such as the “Guidelines for the Seismic Retrofit of Existing Buildings”.
It is important to recognize the value of our existing building stock. Reuse and indeed continued use should properly weigh the seismic safety of a structure as its life is extended. Updating a buildings’ seismic system not only helps save lives, it also works to protect investments and maintain the fabric of our communities.
Another effort in the direction of improving vulnerabilities of existing buildings has been “on the books” for a number of years. The aptly named “Utah Parapet Ordinance” has been an amendment to the Uniform Building Code provisions since 1991 and requires investigation and potential strengthening of pre-1975 building parapets and appendages when reroofing. This provision will be continued into the requirements of the Utah Uniform Building Standard Rules. The enclosed brochure will provide additional information for your use. Should you have need for additional copies of this document, please contact the Structural Engineers Association of Utah or any of the other sponsoring agencies.
We encourage you to become familiar with these provisions and incorporate them into projects beginning in 2002.