Elastic-Plastic Seismic Response of Chimney

An analytic investigation of the elastic and inelastic response behaviors of an 823-ft (251-m) chimney to a realistic earthquake record is conducted. The chimney is modeled by using eight pipe-type beam finite elements. Equations of motion are solved numerically by direct integration method. For the pure elastic analysis, cracks developed in the chimney are considered. Several assumed percentages of the critical damping are also considered. For the inelastic analysis, the material of the chimney is assumed to be an idealized equivalent homogeneous material with the same Young's modulus, mass density, and elastic limit as concrete. Equations for the determination of the depths of elastic-plastic boundaries in the finite elements are derived. The time-history response results obtained from the inelastic analysis are compared with those obtained from the purely elastic analysis. The present method may be applied to the analysis of practical designs of slender reinforced concrete chimneys.