Earthquake response of tall reinforced concrete chimneys

The results from an experimental program have been used to develop a non-linear dynamic analysis procedure for evaluating the inelastic response of tall reinforced concrete chimney structures. The procedure is used to study the inelastic response of ten chimneys, ranging in height from 115 m to 301 m subject to earthquake excitation. Based on the study, a series of code design recommendations have been prepared and incorporated into the 2001 CICIND code to encourage reliance on the development of ductility in reinforced concrete chimneys and to prevent the formation of brittle failure modes. The basis for the selection of a structural response factor of R=2 which halves the seismic design forces is presented. The design recommendations result in both improved performance and cost savings of up to 20% compared with designs undertaken with the 1998 ACI307 and 1998 CICIND codes.