Email Address is required Invalid Email Address
In today’s market, it is imperative to be knowledgeable and have an edge over the competition. ACI members have it…they are engaged, informed, and stay up to date by taking advantage of benefits that ACI membership provides them.
Read more about membership
Learn More
Become an ACI Member
Founded in 1904 and headquartered in Farmington Hills, Michigan, USA, the American Concrete Institute is a leading authority and resource worldwide for the development, dissemination, and adoption of its consensus-based standards, technical resources, educational programs, and proven expertise for individuals and organizations involved in concrete design, construction, and materials, who share a commitment to pursuing the best use of concrete.
Staff Directory
ACI World Headquarters 38800 Country Club Dr. Farmington Hills, MI 48331-3439 USA Phone: 1.248.848.3800 Fax: 1.248.848.3701
ACI Middle East Regional Office Second Floor, Office #207 The Offices 2 Building, One Central Dubai World Trade Center Complex Dubai, UAE Phone: +971.4.516.3208 & 3209
ACI Resource Center Southern California Midwest Mid Atlantic
Feedback via Email Phone: 1.248.848.3800
ACI Global Home Middle East Region Portal Western Europe Region Portal
Home > Tools > Frequently Asked Questions
Q. Does ACI 350-20 allow terminations of vertical reinforcing bars in a wastewater concrete containment tank wall? For example, my calculations show that a cantilevered wall requires vertical bars at 4 in. (102 mm) spacing at the connection to the tank base. At mid-height of the wall, however, the moment can be resisted using the same bar size at 8 in. (203 mm) spacing. Does ACI 350-20 allow for the termination of every other bar? A. Development of flexural reinforcement in nonprestressed members is discussed in Section 12.8.10 of ACI 350-20. That section applies to your containment structure. You may terminate alternate bars as you describe, but the terminated bars must be fully developed at the base and extend at least d or 12db from the point in the moment diagram corresponding to the maximum moment strength of the remaining (nonterminated) reinforcing bars. This is illustrated in Fig. R12.8.10.2. In your case, the remaining bars must extend to the end of the cantilever (less the cover depth). Note that you should also check additional reinforcement design considerations provided in Section 4.4 of ACI 350.4R-04, as they might affect reinforcing details for your containment structure. Finally, note that Fig. R12.8.10.2 has a typo. The extension of the “Bar b” negative reinforcement beyond the inflection point should be labeled (d, 12 db, or ln/16), as the first subscript in the series should be a comma, not a 1. References: ACI 350-20; ACI 350.4-04; ACI CODE-350.3-20 Topics in Concrete: 318 Building Code; Design of Concrete; Tank, Concrete
Q. Does ACI 350-20 allow terminations of vertical reinforcing bars in a wastewater concrete containment tank wall? For example, my calculations show that a cantilevered wall requires vertical bars at 4 in. (102 mm) spacing at the connection to the tank base. At mid-height of the wall, however, the moment can be resisted using the same bar size at 8 in. (203 mm) spacing. Does ACI 350-20 allow for the termination of every other bar?
A. Development of flexural reinforcement in nonprestressed members is discussed in Section 12.8.10 of ACI 350-20. That section applies to your containment structure. You may terminate alternate bars as you describe, but the terminated bars must be fully developed at the base and extend at least d or 12db from the point in the moment diagram corresponding to the maximum moment strength of the remaining (nonterminated) reinforcing bars. This is illustrated in Fig. R12.8.10.2.
In your case, the remaining bars must extend to the end of the cantilever (less the cover depth). Note that you should also check additional reinforcement design considerations provided in Section 4.4 of ACI 350.4R-04, as they might affect reinforcing details for your containment structure.
Finally, note that Fig. R12.8.10.2 has a typo. The extension of the “Bar b” negative reinforcement beyond the inflection point should be labeled (d, 12 db, or ln/16), as the first subscript in the series should be a comma, not a 1.
References: ACI 350-20; ACI 350.4-04; ACI CODE-350.3-20
Topics in Concrete: 318 Building Code; Design of Concrete; Tank, Concrete
Search other resources on the ACI website for answers to technical questions