Research on the Structure System of Bending-Torsion Columns and Spiral Beam Sightseeing Tower

According to the architectural shape and structural characteristics of an actual project, a structural system of sightseeing tower consisting of three twisted columns and one spiral beam was proposed, and the influence laws of column twisting angle θ, spiral beam rotation direction, structural diameter D and number of spiral beam turns n on the period, displacement (lateral stiffness), member force and structural stability of the structural system were analyzed in detail. The analysis results showed that the increase of column twisting angle θ in the range of the studied parameters was unfavorable to the structural force, and the structural diameter D and the number of spiral beam turns n had some influence on the structural force, but the degree of influence of number of spiral beam turns n was smaller than that of column twisting angle θ. The torsion direction of the bending-torsion column was more favorable to the overall stability of the structure when the torsion direction was opposite to that of the spiral beam. The lateral stiffness of the structure decreased when the column twisting angle increased within the studied parameters (θ=0°-360°), and the lateral stiffness of the structure decreased when the structural diameter increased within the studied parameters (D=5-8 m). The lateral stiffness of the structure increased when the number of spiral beam turns increased within the studied parameters (n=7-11). The lateral stiffness of the structure increased when the bent and twisted column was rotated in the opposite direction to the spiral beam. Based on the coil spring transverse static stiffness theory, the lateral stiffness calculation formula of the bending-torsion column and spiral beam structure was established, and the formula calculation results were in good agreement with the software calculation results.