GROUND MOTIONS FOR FEMA P-695 APPLICATION IN SUBDUCTION ZONES

Abstract

THE FEMA P-695 REPORT PRESENTS A METHODOLOGY FOR THE RATIONAL QUANTIFICATION OF SEISMIC PERFORMANCE FACTORS FOR USE IN SEISMIC DESIGN. DESPITE THE FACT THAT THE METHODOLOGY IS COMPREHENSIVE AND COVERS A WIDE RANGE OF POSSIBLE APPLICATIONS, IT ONLY PROVIDES GROUND MOTION SETS RECORDED FROM SHALLOW CRUSTAL EARTHQUAKES. HENCE, THIS PAPER PRESENTS A NEW SET OF GROUND MOTIONS AIMED AT EXTENDING THE SCOPE OF THE FEMA P-695 METHODOLOGY TO ZONES PRONE TO SUBDUCTION EARTHQUAKES. TO CONSIDER THE EFFECT OF SPECTRAL SHAPES ON COLLAPSE CAPACITIES, THE SPECTRAL SHAPE FACTORS SSF WERE COMPUTED. FOUR LIGHT-FRAME BUILDINGS WERE ANALYZED TO STUDY THE IMPACT OF USING THE NEW SUBDUCTION GROUND MOTION SET. RESULTS SHOWED A DECREASE IN COLLAPSE CAPACITIES OF 12.4%, AN INCREASE IN PEAK FLOOR ACCELERATIONS OF 31.7%, AND AN INCREASE IN THE DISSIPATED HYSTERETIC ENERGY OF 15.7%. ADDITIONALLY, THE NUMBER OF GROUND MOTIONS AND THE INTENSITY LEVELS OF THE SET PROVED TO BE ROBUST ENOUGH TO PROVIDE THE SAME RELIABILITY THAT CAN BE OBTAINED WHEN EMPLOYING A MUCH LARGER GROUND MOTION SET. THE GROUND MOTIONS AND THE INFORMATION PROVIDED IN THIS PAPER HAVE BEEN DESIGNED TO BE FULLY CONSISTENT WITH THE FEMA P-695 GUIDELINES. HOWEVER, THEIR APPLICATION CAN BE EXTENDED TO OTHER ANALYSES THAT EVALUATE THE SEISMIC PERFORMANCE OF STRUCTURAL SYSTEMS IN SUBDUCTION AREAS. A DATABASE THAT INCLUDES THE PROPOSED GROUND MOTION SET IS AVAILABLE ONLINE.