Thermal Analysis of 120m high RC Chimney

Abstract

This paper deals with the thermal analysis of 120m high, RC chimney. The aim of the study is to find the distribution of internal forces caused by thermal loads, resulting from the difference among the ambient and the operating temperature. Namely, during the operating process, the higher temperature regime than those in the main design, has caused the thermo insulation damage, indicating the possible exceeding of ultimate strength in the concrete and reinforcement of chimney wall. It was assumed that temperature variation is uniform over the surface and linearly varying through the thickness of the chimney. Numerical analysis is performed using four-node shell element and the commercial program SAP2000. The finite element model is verified comparing the results of the thermal analysis with the available ones in the literature. The study shows that thermal radial forces and radial moments, obtained by the higher operating temperatures, are greater then the one in the original design. Furthermore these forces can cause cracks in vertical direction, so appropriate retrofit measures are to be applied.