Design of Steel Chimney Liners

Several structural problems which arise in the design of bottom-supported, steel chimney liners are reviewed. The loads which a liner must sustain include dead weight, bending due to wind, seismic, thermal gradients and stack draft. Thermal gradients can cause stresses which are quite high. However, the magnitude of these stresses depend not only on the temperature differences, but on the spatial distribution of the variation. Liners are thin cylindrical shells; localized buckling is, therefore, the principal failure mode. Because liners are subject to biaxial compression, an interaction formula is given to cover this situation as present design codes generally cover only uniaxial stress states on very special biaxial states. A design procedure is presented which covers a number of different loading combinations.