Wind loads on curved roofs: effect of side walls

Abstract

Wind tunnel pressure measurement studies on a rigid model (scale 1:300) of structure with curved roof has been carried out under open and suburban terrain conditions. The external pressures exerted over the roof due to the presence of side walls have been investigated for the following test cases: (i) roof springing from ground level i.e., side wall height, h = 0.0d and (ii) roof at elevated levels i.e., h = 0.15d and 0.29d, where ‘d’ is span of the roof. The model has been instrumented with point pressure taps on the roof and area averaged pressure taps on the gable end wall and sidewalls. In this paper, results pertaining to mean and standard deviation of pressure coefficients, (Cpe and Cpe ), at edge and mid arch locations on the roof for typical angles of wind incidence i.e., wind blowing (i) parallel (θ = 0°), (ii) perpendicular (θ = 90°), and (iii) diagonal w.r.t. normal to gable end (θ = 45°) have been presented. Based on the study, it is observed that the centre half and windward region of the roof of the model with h = 0.29d is subjected to high suction than that for model with h = 0, which is due to the presence of sidewall. Further, evaluated values of Cpe for wind blowing parallel and perpendicular to the axis of the arch have been compared with values given in codes of practice and the evaluated values are observed to be between two values reported in AS/NZS and ASCE/SEI codes of practice for θ = 0° and reasonable agreement at windward quarter for θ = 90°.