Seismic Base Shear Calculator
Estimate the seismic base shear on a building from its weight, site spectral acceleration and response modification factor using the equivalent lateral force method.
How to Use the Seismic Base Shear Calculator
- Enter the effective seismic weight of the building in kN.
- Enter the design short-period spectral acceleration S_Ds.
- Enter the response modification factor R for your lateral system.
- Click Calculate.
Casi d'Uso
- •Preliminary seismic design.
- •Teaching structural dynamics.
- •Quick sanity checks on more complex analyses.
Formula
V = C_s · W, with seismic response coefficient C_s = S_Ds / R.
Domande Frequenti
Which code does this follow?
The simplified equivalent lateral force procedure is common to ASCE 7, Eurocode 8 and СП 14.13330. Values of S_Ds and R come from code-prescribed tables.
What if the building is irregular?
Irregular structures require dynamic analysis (modal response spectrum or time history). This calculator is only appropriate for regular, short-period buildings.
How do I choose R?
R depends on the lateral system: roughly 3 for ordinary steel moment frames, 5 for ordinary reinforced concrete walls, 8 for special moment frames. Consult the governing code.