ACI 350.3-01 Seismic Design of Liquid-Containing Concrete Structures (ACI 350.3-01) and Commentary (ACI 350.3R-01).
As the “loading side” of seismic design is outside the scope of Chapter 21, ACI 318, it was decided to maintain this practice in ACI 350 as well. Accordingly, the basic scope, format, and mandatory language of Chapter 21 of ACI 318 were retained with only enough revisions to adapt the chapter to environmen- tal engineering structures. This approach offers at least two ad- vantages: (a) It allows ACI 350 to maintain ACI 318’s practice of limiting its seismic design provisions to the “resistance side” only; and (b) it makes it easier to update these seismic provi- sions so as to keep up with the frequent changes and improve- ments in the field of seismic hazard analysis and evaluation.
5.3—Dynamic force distribution above base 5.3.1—Rectangular tanks Walls perpendicular to the earthquake force and in the leading half of the tank shall be loaded perpendicular to their plane (dimension B) by: (a) the wall’s own iner- tia force P w ′ ′ ; (b) one-half the impulsive force P i ; and (c) one-half the convective force P c . Walls perpendicular to the earthquake force and in the trailing half of the tank shall be loaded perpendicular to their plane (dimension B) by: (a) the wall’s own inertia force P w ′ ′ ; (b) one-half the impulsive force P i ; (c) one- half the convective force, P c ; and (d) the dynamic earth and ground water pressure against the buried portion of the wall. Walls parallel to the direction of the earthquake force shall be loaded in their plane (dimension L) by: (a) the wall’s own in-plane inertia force P w ′ ′ ; and (b) the in- plane forces corresponding to the edge reactions from the abutting wall(s). Superimposed on these lateral unbalanced forces shall be the lateral hydrodynamic force resulting from the hydrodynamic pressure due to the effect of vertical acceleration p vy acting on each wall.
R1.1—Scope This document is a companion document to Chapter 21 of the American Concrete Institute Committee code 350, “Code Requirements for Environmental Engineering Concrete Structures (ACI 350-01) and Commentary (350R-01).” (1) This document provides directions to the designer of liquid- containing concrete structures for computing seismic forces that are to be applied to the particular structure. The designer should also consider the effects of seismic forces on compo- nents outside the scope of this document, such as piping, equipment (for example, clarifier mechanisms), and connect- ing walkways, where vertical or horizontal movements between adjoining structures or surrounding backfill could adversely influence the ability of the structure to function properly. (2) Moreover, seismic forces applied at the interface of piping or walkways with the structure may also introduce appreciable flexural or shear stresses at these connections.ACI 350.3 pdf download.