Building & Seismic
For chord force estimate.
Levels (top → bottom)
| Level | w_i (kN) | F_i (kN) | w_px (kN) | Σw_x↑ | ΣF_x↑ | Fpx (kN) | Fpx/w_px | w (kN/m) | Mmax (kN·m) | Chord T (kN) |
|---|
Method
Fpx = (Σ Fi from level x to top) / (Σ wi from level x to top) × wpx. Bounded by Fpx,min = 0.2·SDS·Ie·wpx and Fpx,max = 0.4·SDS·Ie·wpx. Per-meter loading w = Fpx / L. Maximum diaphragm moment M = w·L²/8 (simply-supported). Chord tension T = M / d. For each level, w_i (story weight) and F_i (story design force from ASCE 7 §12.8) are inputs. w_px is the diaphragm-tributary weight.