Experimental study of wind loads and wind-induced vibration on large single column-supported two-plate billboard

Abstract:

To study the wind-induced destroy mechanism and improve the wind-resistance design for outdoor large single-column billboards, two kinds of wind tunnel experiments were conducted on a typical two-plate billboard. Based on synchronous pressure measurement test, the coefficients of horizontal force that is parallel to and perpendicular to plate, and torque loads coefficients in different wind directions were investigated, the wind pressure distribution along width of board and wind force coefficient of structure at most unfavorable wind directions were diagramed, and the analytic power spectrums density (PSD) of the horizontal and torsional wind loads were given. According to the aero-elastic model test by utilizing high frequency force balance (HFFB), the wind-induced force responses at the bottom of the two-plate billboard with flexible column were analyzed. The theoretical methods that calculate billboard's wind-induced dynamic responses in horizontal and torsional directions were proposed based on the analysis of experiments. The results indicate that the PSD of wind loading which is perpendicular to plate needs to take aerodynamic admittance function into consideration. The excitation from turbulence and vortex shedding are the main contribution to torsional load spectrum. The aerodynamic damping in two directions (i.e. perpendicular to plate and torsion) has a significant influence on wind-induced vibration of billboard. The theoretical approach is validated through the wind tunnel experiment, and it can be applied in predication for wind load effect on billboards.