| Summary |
Design wind force coefficients for H.P.-shaped porous canopy roofs made of shade cloth fabrics have been investigated based on a series of wind tunnel experiments as well as on a CFD analysis. For discussing the design wind force coefficients focus is on the axial forces as the load effect, assuming that the roof is rigid and supported by four corner columns. The parameters under consideration are rise/span ratio, porosity and angle of roof inclination. The roof models are made of 1mm thick perforated plastic plates, the porosity of which is changed from 0 (solid) to 0.4. The overall aerodynamic force and moment coefficients are measured in a turbulent boundary layer with a six-component force balance or a Y-shaped force balance that was designed, built and gauged for this experiment. The CFD analysis using a RANS model is made for solid roofs to understand the flow field around the model and the pressure distributions on the roof surfaces, although only the time-averaged wind pressures are obtained. The effects of the above-mentioned parameters on the aerodynamic force and moment coefficients are investigated. Based on the results, the design wind force coefficients are proposed as a function of these parameters for the two wind directions parallel to the diagonals of the roof. The validity of the wind force coefficients is verified by a comparison of the load effects predicted by the wind force coefficients with the maximum peak values of the load effects obtained from a time history analysis. |