Aci-350.3-06.pdf -

The Engineer’s Guide to ACI-350.3-06.pdf: Seismic Design for Environmental Concrete Structures

5. Freeboard Requirements (Sloshing Height)

The fundamental concept behind ACI 350.3 is that a tank full of water does not act as a rigid mass. During an earthquake, the water moves in two distinct ways, creating two different types of forces:

• SUG I: Low hazard to life (e.g., irrigation reservoirs)
• SUG II: Moderate hazard (standard water storage)
• SUG III: High hazard (wastewater treatment where failure causes environmental disaster or loss of drinking water).

Conclusion: Why Every Environmental Engineer Needs This PDF

Unlike buildings (Risk Categories), ACI 350.3 defines three Seismic Use Groups: ACI-350.3-06.pdf

Where (P_i) is impulsive force, (W_i) is impulsive liquid weight, and (S_DS) is the short-period spectral acceleration from the site geology. The convective force uses (S_D1) (1-second period) instead. The Engineer’s Guide to ACI-350