# 2.12. Standard Wind Speed Conversions¶

Since the wind speed (\(V(600s, 10m, z_0)\)) from the NJcoast SHP Tool is averaged over a time window of 1 hour, a number of standard conversions parse the wind speed to the 3-second and open-terrain PWS (i.e., \(V(3s, 10m, Exposure C)\)):

1. Compute \(\alpha\) and \(z_g\) by ASCE 7-16 ([ASCE16]) Equation C26.10-3 and C26.10-4 taking \(c_1 = 5.65, c_2 = 450\) for units in m):

Compute the gradient height \(V(600s, z_g, z_0)\) using the power law expression:

3. Compute the Exposure C (open-terrain) wind speed at 10m height \(V(600s, 10m, Exposure C)\), with \(\alpha_C = 9.5\) and \(z_{g,C} = 274.32 m\) ([ASCE16]):

Convert the result to 3s-gust wind speed using the ESDU conversion [ESDU02]:

where \(C(3s) = 1.52\) and \(C(600s) = 1.05\) are the Gust Factors from the ESDU conversion.

- ASCE16
ASCE (2016), Minimum Design Loads for Buildings and Other Structures, ASCE 7-16, American Society of Civil Engineers.

- ESDU02
Engineering Sciences Data Unit (ESDU). (2002). “Strong winds in the atmospheric boundary layer—Part 2: Discrete gust speeds.” ESDU International plc, London, U.K.