- See Section 2.173.
- Response parameter is acceleration for 5% damping.
- Find b2 and b3 significantly different than 0 at 5% level for all periods but bA and bS not significant for
many periods (especially for vertical component).
- Find deamplification for vertical component on soft and stiff soil compared with rock. Check by removing
all 34 Northridge records (many of which were on soft soil) and repeat analysis; find little change.
- Also derive equations for horizontal response under influence of vertical acceleration using a bending SDOF
model; find little change in response.