Seismic Analysis and Design of Industrial Chimneys by Using Staad Pro

Our project describes a simplified method that allow obtaining the fundamental period of vibration, lateral displacement, shear force and bending moment through a set of equations, obtaining for all cases studied an error below 10%.The results obtained in this study were applied to a total of 9 real chimneys (4 of steel and 5 of reinforced concrete) built in Chile, with the objective of calibrating founded expressions. During the stage of the analysis, it was verified that the criterion of consistent masses provide better results than the criterion of lumped masses, and as a very important conclusion a discrete analysis of the model in twenty segments of the beam is satisfactory. The most representative variables that define the model with which it is possible to carry out a parametric analysis of the chimney. As important parameters we could refer to: slenderness ratio H/Dinf, radius ratio Rsup/Rinf, thickness ratio Esup/Einf and thickness diameter ratio Dinf/Einf. Later, by varying each one of the chosen parameters several analyses of representative chimneys of this great family, could be carried out. As seismic loads, the spectrums of accelerations recommended by the code of seismic design for structures and industrial installations in Chile, have been considered. Modal responses were combined using the combination rule CQC.In all the cases studied in this investigation, the influence of the P effect, the soil structure interaction, and the influence on responses that provoke the inclusion of lining, have been disregarded.