Behavior of tall masonry chimneys under wind loadings using CFD technique

This study deals with the static behavior of a self-supporting traditional clay brick-gypsum mortar masonry chimneys representative of the large number of chimneys currently used in industrial field in Iraq which plays an important role in dispersion of flue gases and smoke releasing to the atmosphere. The first part of the present study is devoted to review the construction process of chimneys, their shapes and dimensions, and properties of masonry units in which chimneys with heights 45, 50, 60, 70 and 80 m were studied. The second part focused on the wind loading analysis using CFD modelling and compared it with wind loads obtained by ASCE7-10, where three wind velocities were taken 30, 42, and 50 m/s. The third part related to 3D numerical model using finite elements method via ANSYS 2020R1 software to study the structural behavior of chimneys under gravity and wind loads in term of deflections and stresses. It is found that chimneys with slenderness ratio up to 11.6 (height = 60 m) re satisfied the design codes requirements for all wind velocities 30−50 m/s for permissible tensile stress, namely with a the factor safety greater than 2.The lateral deflection at the top of the chimney, of heights 45 m and 50 m, for all wind velocities is within permissible limit i.e. (H/650).Wind loadings estimated by CFD analysis is greater than that calculated by ASCE7−10 by about 37 %.