Why equivalent lateral force procedures allocate larger storey shears toward upper levels using height‑weighted tributary mass?
Choices
- (A) Always concentrate shear at foundations regardless of height
- (B) Contractors dictate storey allocation
- (C) Higher elevations participate more in lateral acceleration patterns per modal shape approximations
- (D) Delete base storey shear arbitrarily
Correct answer: (C)
Higher elevations participate more in lateral acceleration patterns per modal shape approximations
Explanation
First-mode shapes lift upper mass participation in seismic distribution.