ACI 307-08

This code gives material, construction, and design requirements for cast-in-place and precast reinforced concrete chimneys. It sets forth minimum loadings for design and contains methods for determining the concrete and reinforcement required as a result of these loadings. The method of analysis applies primarily to circular chimney shells; however, a general procedure for analysis of noncircular shapes is included.Equations are provided for determining the temperature gradient through the concrete resulting from the difference in temperature of the gases inside the chimney and the surrounding atmosphere. Methods for combining the effects of dead and wind (or earthquake) loads with temperature, both vertically and circumferentially, are included in this code. These methods permit the licensed design professional to establish minimum concrete and reinforcement requirements.The Commentary discusses some of the background and considerations of Committee 307 in developing the provisions contained in Code Requirements for Reinforced Concrete Chimneys (ACI 307-08). Two appendixes provide the derivation of the equations for nominal strength and temperature stresses. Commentary provisions begin with an R, such as R1.1.1, and are shown in italics.