Seismic load calculator

Calculate base shear and seismic response

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The Seismic Load Calculator helps structural engineers determine seismic forces on buildings according to ASCE 7 standards. Calculate base shear, seismic response coefficients, and lateral forces for earthquake-resistant design.

Seismic loads are critical for structural design in earthquake-prone regions. ASCE 7 provides comprehensive procedures for calculating seismic forces based on building location, site conditions, structural system, and building weight.

Enter building weight, site class, spectral accelerations (SDS, SD1), and response modification factor (R) to calculate seismic response coefficient and base shear. The calculator uses simplified ASCE 7 methods for preliminary seismic load estimation.

Features

Everything you need

Base shear calculations
Seismic response coefficient determination
Site class considerations
Response modification factor support
Spectral acceleration inputs
Simplified ASCE 7 method
Imperial and metric units

How it works

Simple workflow

1
Enter building weight
2
Select site class (B, C, D, E)
3
Input spectral accelerations (SDS, SD1)
4
Specify response modification factor (R)
5
Review calculated base shear

Use cases

Built for real-world scenarios

Structural design

Calculate seismic loads for lateral force resisting system design.

Code compliance

Verify designs meet ASCE 7 seismic requirements for building code compliance.

Retrofit analysis

Evaluate existing building seismic capacity and retrofit requirements.

Preliminary design

Get quick seismic load estimates during early design phases.

FAQ

Frequently asked questions

Base Shear V = Cs × W, where Cs is seismic response coefficient and W is building weight. Cs = SDS/(R/Ie) for short-period structures, with upper and lower limits per ASCE 7.

Site class describes soil conditions: B (rock), C (soft rock/stiff soil), D (stiff soil), E (soft soil). Site class affects spectral accelerations and seismic response.

R-factor accounts for structural system ductility and overstrength. Higher R-values (8-8.5) for ductile systems like steel moment frames, lower (2-3) for non-ductile systems.

SDS and SD1 come from ASCE 7 seismic maps based on building location and site class. They represent short-period and 1-second spectral accelerations adjusted for site conditions.

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