New Site Coefficients, Fa, Fv, and Fpga, in ASCE 7-16

Why: The American Society of Civil Engineers' ASCE 7, Minimum Design Loads for Buildings and Other Structures, the forerunner of earthquake codes for buildings in this country, was in 1988 and will be published in a new edition in 2016. The new edition (ASCE-16) will include updated coefficients for acceleration responses of the soil to short periods (Fa), long period (Fv) and zero periods (Fpga) of an earthquake.

What: Standard ASCE 7 provides requirements for general structural design and includes means for determining dead, live, soil, flood, wind, snow, rain, atmospheric ice, and earthquake loads, and their combinations that are suitable for inclusion in building codes and other documents. ASCE 7 is and integral part of the building codes of the United States. Structural engineers, architects, and those engaged in preparing and administering local building codes will find the structural load requirements essential to their practice.

How: The existing site factors in ASCE 7-10 are based on on the 1989 Loma Prieta ground motion data numerous generic site response analyses, and judgement. The new site factors in ASCE 7-16 are updated based on:statistical analysis by a 12-person project team of NGA West 2 database (which houses 104 records) and a three-year Pacific Earthquake Engineering Research Center (PEER) study by J. Stewart, PE.