SEAONC BUILDING RATINGS SUB-COMMITTEE
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SEAONC sub-committee members have worked for eight years to develop the Earthquake Performance Rating System

In 2006, responding to a request from the Board of the Structural Engineers Association of Northern California (SEAONC), the Existing Buildings Committee agreed to form a subcommittee to study the feasibility of and development of an Earthquake Performance Rating System (EPRS). Phase 1, the feasibility phase, was completed in January 2008 and a paper summarizing the results was included in the 2008 SEAOC Convention Proceedings (SEAONC EBC BRS, 2008). Progress on Phase 2 was presented at the ATC-SEI 2009 conference and the 2011 and 2012 SEAOC Convention Proceedings (SEAONC EBC BRS, 2009, 2011 and 2012).

In March 2011, the subcommittee collaborated with ATC to hold ATC 71-2, a workshop to gather feedback from building owners, investors, and policy-makers regarding the utility of an EPRS. The intent in gathering this feedback was to obtain input from potential users regarding the scope and structure of the ratings system. This workshop resulted in the inspiration to form the USRC – see USRC History.

The SEAONC sub-committee continued its work and presented an update in the 2012 SEAOC Convention Proceedings (SEAONC EBC BRS, 2012. This paper describes the completion of the rules for deriving a three-part rating from evaluations based on the ASCE 31-03 standard, Seismic Evaluation of Existing Buildings. The paper also summarizes the beta testing that was performed. In June 2012 the sub-committee asked volunteer engineers to apply the draft EPRS to completed ASCE 31 evaluations. Eleven engineers, seven of whom were seeing the EPRS for the first time, produced ratings for 21 buildings. The findings are included in the paper.

The SEAONC EPRS is not a new assessment tool, and it does not replace any of the tools engineers currently use to evaluate buildings. Instead, the EPRS repackages the findings of other tools and methodologies, translating them into consistent, comparable, jargon-free terms.

The SEAONC EPRS will eventually support derivation of a rating from a number of common evaluation methods, ranging from a simple walk-through and review of plans, to quantitative assessments such as FEMA 154 (FEMA, 2002). To start the sub-committee focused on the comprehensive national standard known as ASCE 31, Seismic Evaluation of Existing Buildings (ASCE, 2003). The sub-committee developed a “translation matrix”, to convert ASCE 31 outputs into EPRS ratings.

A full presentation of the SEAONC EPRS is provided in pdf format in the Technical Resources segment.

The SEAONC sub-committee members that worked for most of the past eight years include:

  • Ron Mayes – Co-Chair
  • Marguerite Bello – Co-Chair
  • Kate Stillwell – Past Co-Chair
  • Mathew Bittleston
  • Stephen Bono
  • David Bonowitz
  • Craig Goings
  • Doug Hohbach
  • David McCormick
  • Evan Reis

ATC, 2011. ATC-71-2, “Proceedings for a Workshop on a Rating System for the Earthquake Performance of Buildings,” May 2011, Applied Technology Council.

SEAONC Existing Buildings Committee, Building Ratings Subcommittee, 2008. “Report Cards for Buildings: A Proposed Rating System for Earthquake Performance,” Proceedings, 77th Annual Convention, Structural Engineers Association of California.

SEAONC Existing Buildings Committee, Building Ratings Subcommittee, 2009. “Report Cards for Buildings: A Proposed Rating System for Earthquake Performance,” in Proceedings of the 2009 ATC&SEI Conference on Improving the Seismic Performance of Existing Buildings and Other Structures, San Francisco, December 9-11.

SEAONC Existing Buildings Committee, Building Ratings Subcommittee, 2011. “SEAONC Rating System for the Expected Earthquake Performance of Buildings,” Proceedings, 80th Annual Convention, Structural Engineers Association of California.

SEAONC Existing Buildings Committee, Building Ratings Subcommittee, 2012. “SEAONC’s Earthquake Performance Rating System: Translating ASCE 31-03,” Proceedings, 81st Annual Convention, Structural Engineers Association of California