Inputs
design short period
design 1-sec period
long-period transition (s)
e.g. SMRF=8, OMRF=3.5
0.9 steel MRF, 0.9 conc, 0.75 other
heights in m or ft, weights in kN or kip
Method & assumptions
- Ta = Ct·hnx (ASCE 7 Eq. 12.8-7).
- Cs = SDS/(R/Ie); ≤ SD1/(T·R/Ie) (or T·TL for T>TL); ≥ 0.044·SDS·Ie ≥ 0.01.
- V = Cs·W. Distribution Fx = Cvx·V; Cvx = wx·hxk / Σ.
- k = 1 if T ≤ 0.5 s, 2 if T ≥ 2.5 s, linearly interpolate otherwise.
- Site coefficients Fa, Fv not handled here — provide SDS, SD1 directly.
Results
Ie (importance factor)—
hn (top of structure)—
Approximate Period Ta—
Effective Weight W—
Seismic Coeff Cs—
Base Shear V—
Distribution exponent k—
Force Distribution per Level
| Level | h (m/ft) | w | w·hk | Cvx | Fx |
|---|