What Is the Equivalent Lateral Force Procedure?
ELF (the ASCE 7 12.8 — the static; the seismic) distributes (the base shear — the V; the height's — the triangular) to (the levels — the Fx; the k's — the exponent). The procedure: the V's (the CsW; the 12.8.2's), the distribution's (the Cvx; the k's — the period's), and the limits (the regular's — the permitted; the 12.6's). The seismic's — the static standard.
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How ELF works
The V (the CsW — the coefficient's; the R/Ie's — the reduced), the Cs (the SDS/R — the computed; the min/max's — the 12.8.2's), the distribution (the Cvx — the wx*hx^k; the k's — the 1-2; the period's), and the torsion (the accidental's — the 5%; the Ax's).
The requirements
The regular (the permitted — the 12.6's; the SDC's — the limits), the 3D (the model's — the required; the torsion's), the drift (the Cd's — the amplified; the checked), the P-delta (the theta's — the 0.10's), and the scaling (the RSA's — the 100%'s; the 12.9.4's).
Vs. the dynamic
The ELF's (the simple — the regular's; the low-rise's), the RSA's (the modal — the irregular's; the SDC D's), the NRHA's (the history's — the tall's; the PBSD's), and the selection (the 12.6's — the permitted; the height's — the limits). The ELF is the baseline — the V computed, the Fx distributed.
The bottom line
Apply ELF per ASCE 7 12.8 (V = CsW, distribute via Cvx with k=1-2 by period) for regular structures within Table 12.6-1 limits — use RSA/NRHA for irregular, tall, or high-SDC buildings.
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