Characteristics of local wind forces on the edges of signboards installed on the rooftops of buildings

Abstract Many signboards are installed on the rooftops of low- and middle-rise buildings in Japan, which are often damaged by strong winds. However, there are no specifications of wind force coefficients for such signboards in the Japanese building codes and standards. In the present study, wind tunnel experiments were conducted to collect data on wind force coefficients under various conditions, including building shapes, as well as signboard shapes and locations. The distributions of the maximum peak wind force coefficients were obtained at various wind angles. Based on the results, the variation of the maximum peak wind force coefficient with wind angle was investigated. It was found that very large wind forces occurred near the edges of the signboard at oblique wind angles ranging from 30° to 60° with respect to the outside surface of the signboard. The present study focuses on such conditions that cause large wind forces on signboards. The results indicate that the building shape significantly affects the maximum peak wind force coefficient.