Aci-350.3-06.pdf: |link|
One of the most practical sections in ACI-350.3-06.pdf is Chapter 6: Freeboard . It calculates the maximum vertical height of sloshing waves. If the tank roof is too low, the liquid will slam into the roof, causing structural damage or overflow. The code mandates a minimum freeboard based on the site's (S_D1) and tank radius.
Unlike static water pressure (triangle shape), seismic pressure creates an inverted trapezoid or a more complex curve. The PDF contains lookup tables and coefficients to redraw those pressure diagrams for concrete design. ACI-350.3-06.pdf
If you have just downloaded ACI-350.3-06.pdf, here is the standard engineering workflow for designing a new circular water tank in Seismic Design Category C (SDC C): One of the most practical sections in ACI-350
Determine site class and spectral accelerations (S_S) and (S_1) from USGS maps. Step 2: Convert to (S_DS) and (S_D1) per ASCE 7-05 (the partner code to this -06 edition). Step 3: Go to Section 4.2 of the PDF. Compute the height-radius ratio (H/R). Step 4: Use Table 4.2.1 to find the impulsive mass ratio ((W_i / W)) and convective mass ratio ((W_c / W)). Step 5: Calculate the impulsive base shear (V_i) and convective base shear (V_c). Step 6: Combine loads per Section 4.5 ((V = \sqrtV_i^2 + V_c^2) for circular tanks; (V = V_i + 0.5V_c) for rectangular tanks). Step 7: Check sloshing height (Chapter 6). If height > freeboard, raise the wall or shorten the radius. Step 8: Design reinforcing bars following Chapter 7 (hoops at 4-inch spacing in plastic hinge zones). The code mandates a minimum freeboard based on