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.
Keywords: chimneys; compressive strength; concrete construction; earthquake- resistant structures; formwork (construction); foundations; high temperature; linings; loads (forces); moments; openings; precast concrete;quality control; reinforced concrete; reinforcing steels; specifications; static loads; strength; structural analysis; structural design; temperature; thermal gradient; wind pressure.
Table of Contents
Chapter 3—Construction requirements
Chapter 4—Loads and general design criteria
4.4—Special design considerations and requirements
4.5—Wind deflection criteria
Chapter 5—Design of chimney shells: strength method
5.5—Nominal moment strength: circular shells
5.7—Design for circumferential bending
Chapter 6—Thermal stresses
6.2—Vertical temperature stresses
6.3—Circumferential temperature stresses
7.1/R7.1—Referenced standards/Referenced standards and reports
Appendix A—Derivation of equations for nominal strength
Appendix B—Derivation of equations for temperature stresses