Code Requirements for Reinforced Concrete Chimneys (ACI 307-08) and Commentary

Description

As industry expanded in the years immediately following World War I and, as a result of the development of large pulverized coal-fired boilers for the electric power-generatingutilities in the 1920s, a number of large reinforced concrete chimneys were constructed to accommodate these new facilities. A group of interested engineers who foresaw the potential need for many more such chimneys, and who were members of the American Concrete Institute, embarked onan effort to develop rational design criteria for these structures. The group was organized into ACI Committee 505 (predecessor to the present Committee 307) to develop such criteria in the early 1930s.

Committee 505 submitted a “Proposed Standard Specifica-tion for the Design and Construction of Reinforced Concrete Chimneys,” an outline of which was published in the ACIJOURNAL (ACI Committee 505 1934). This specification was adopted as a tentative standard in February 1936. Although this tentative standard was never accepted by ACI as an official standard, it was used as the basis for the design of many chimneys. As these chimneys aged, inspections revealed considerable cracking. When the industrial expansion began following World War II, other engineers recognized the need for developing an improved design specification for reinforced concrete chimneys.

In May 1949, Committee 505 was reactivated to revise the tentative standard specification, embodying modifications thatwere found desirable during the years it had been in use. The section dealing with the temperature gradient through the chimney lining and the chimney shell was completely revisedand extended to cover different types and thicknesses of lining sand both unventilated and ventilated air spaces between thelining and the concrete shell. In 1954, this specification was approved as ACI 505-54 (ACI Committee 505 1954).