Do I need to install anything?

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For Engineers · Seismic Base Shear

Seismic Base Shear for a stair stringer

Built for engineers using it for real design work. Go from concept to a running model in the browser, then scale to the cloud when needed. Simulate a stair stringer live below — adjust the inputs and watch it respond, right in your browser.

Seismic Base ShearLive

equivalent lateral force

Controls

Presets

Number of stories

Weight per floor (kN)

Design accel. SDS (g)

Response factor R

Importance factor I

The equivalent lateral force method estimates the total earthquake base shear as V = Cs·W, where the seismic coefficient Cs scales the design acceleration by the structure's ductility (R) and importance (I). The base shear is distributed up the building, concentrating force at the top. Educational tool, not a code design.

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Data Inspector

Seismic coeff. Cs0.150

Total weight W9,000 kN

Base shear V1350 kN

Roof force386 kN

Governing equation

V = C_{s} W = min (\frac{S _{D S} I}{R}, 0.15) W = 0.150 \times 9, 000 = 1350 kN

Reading this result: Cs would be 0.167 but is capped at 0.15, so base shear is code-floored here — cutting R further will not add demand.

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Frequently asked questions

Is this good for engineers?: Yes — this version of "Seismic Base Shear for a stair stringer" is framed for engineers using it for real design work. Go from concept to a running model in the browser, then scale to the cloud when needed.
Do I need to install anything?: No. It runs in any modern browser, free, with no account required.