ACI 350-20 (IN-LB, SI) PDF Download

The Code Requirements for Environmental Engineering Concrete Structures (ACI 350-20) is a standard that provides guidelines for the structural design, material selection, and construction of concrete structures used in environmental engineering applications. These structures are used for conveying, storing, or treating water and wastewater, as well as other liquids and solid waste. The standard also covers the evaluation of existing environmental engineering concrete structures.

Environmental engineering concrete structures are subject to unique loadings and severe exposure conditions, which require more stringent serviceability requirements and longer service lives compared to non-environmental structures. Loadings include dead and live loads, earth pressure loads, hydrostatic and hydrodynamic loads, and vibrating equipment loads. Exposures include concentrated chemicals, alternating wetting and drying, high-velocity flowing liquids, and freezing and thawing of saturated concrete. The serviceability requirements include liquid-tightness, gas-tightness, and durability.

The standard emphasizes the importance of proper design, materials, and construction techniques to ensure that the concrete structures are dense, durable, nearly impermeable, and resistant to relevant chemicals, with limited deflections and cracking. It also addresses the need to minimize leakage and control the infiltration of, or contamination to, the environment or groundwater.

The standard incorporates some portions of the ACI 318 building codes that are applicable to environmental engineering concrete structures. The accompanying Commentary explains the rationale behind the provisions of the ACI 350 Code and its relationship with ACI 318. It provides additional explanations for certain requirements and refers to research data for further study. The Commentary follows the same chapter and section numbering as the Code.

Various topics are covered in the standard and the Commentary, including drawings and specifications, inspections, materials, concrete quality, mixing and placing, forming, embedded pipes, joints, reinforcement details, analysis and design, strength and serviceability, flexural and axial loads, shear and torsion, development of reinforcement, slab systems, walls, footings, precast and prestressed concrete, shell structures, folded plate members, seismic design provisions, and an alternate design method in Appendix A.

The standard also references other applicable specifications and standards for the quality and testing of materials used in construction, as well as welding of reinforcement. Criteria for liquid-tightness and gas-tightness testing can be found in ACI 350.1.