SSI ANALYSIS OF TALL CHIMNEYS WITH ANNULAR RAFT CONSIDERING VARIABLE SOIL PROFILE

SSI analysis of a 200m reinforced concrete chimney with annular raft foundation under along - wind load is carried o ut in the present study. To study the effect of geometrical properties of chimney, different ratios of height to base diameter(slenderness ratio) are selected. The ratio of outer diameter to thickness of raft were also varied. To understand the effect of flexibility of soil, variable soil profile is considered below the foundation. Three different soil layers were considered below the foundation. Along - wind loads are calculated as per IS:4998 - 1992. Three dimensional analysis of chimney was carried out using ANSYS software. Lateral tip deflection in chimney and the settlement in raft were obtained in the analysis. The results show that the responses in chimney are affected by the flexibility of soil, slenderness ratio of chimney and thickness of raft.