Influence of Wind Tunnel Test Duration on Wind Load Factors

A method is presented for calculating the uncertainty associated with the estimation of peak pressure coefficients from wind tunnel test records of various lengths and how this uncertainty influences design wind effects. The proposed method is applicable to any type of structure and any type of civil engineering aerodynamic testing facility, including large-scale facilities. As an example of the application of the method, an investigation is presented of time series belonging to five categories of pressure coefficients implicit in Chapter 27 of the ASCE 7-10 Standard. The results of the investigation show that, for typical civil engineering wind tunnels, estimated design wind effects based on tests with durations as low as 10 s, corresponding to prototype durations of less than 6 min, are larger than their counterparts based on tests with 100 s duration by only approximately 5%. The proposed method provides useful indications on minimum lengths of pressure records to be measured in wind tunnels.