Wind tunnel experiments were conducted on 51 models to investigate the characteristics of negative peak wind forces at the edges of rooftop signboards. The peak wind force occurred when the wind direction was parallel to the signboard. For one selected model, simultaneous measurements of wind angle and velocity of inflow, wind pressures on the building, and wind forces at the signboard edge were performed. The spectral analysis of these parameters revealed two flow mechanisms causing the peak wind forces: i.e., alternating vortices shed from the building and inflow turbulence, which are influenced by the building’s aspect ratio or height.
