Failure of wood buildings in earthquake quake ground motion Shake table tests on full-scale wood buildinas in Nat Earthquake Loads Equivalent static base shear M V=ST,MEWI(RR。 factor R F+F+F Failure of wood buildings in earthquakes Northridge earthquake, California, 1994 Kobe earthquake, 1995 7 Earthquake ground motions Fault • Magnitude measures amount of energy released • Distance shaking decays with distance • Local soil conditions shaking damps in hard rock, but amplifies in soft soil 8 Shake table tests on full-scale wood buildings 9 2. Earthquake Loads & Effects in National Building Code of Canada (NBCC), 2005 10 Base shear V = F1+F2+F3 Earthquake Loads F1 = M1 .a1 F3 = M3 .a3 F2 = M2 .a2 M3 M1 M2 Ground motions 11 V = S(Ta )Mv IEW / (RdRo ) where S(Ta ) = design spectral acceleration; Ta = fundamental period; e.g., 0.05(hn ) 3/4 for wood structures with shear walls; Mv = higher mode factor; IE = earthquake importance factor; W = total building weight; Rd = ductility-related force modification factor; and Ro = over-strength related force modification factor Equivalent static base shear 12