Civil Engineering Reference
In-Depth Information
Figure 2.3
Analysis of East Sale data using the
Gringorten fitting method.
Table 2.3
Prediction of extreme wind speeds for East Sale
(synoptic winds)
Return
period
(years)
Predicted gust speed
(m/s) (Gumbel)
Predicted gust speed
(m/s) (Gringorten)
Predicted gust speed
(m/s) (method of
moments)
10
33.8
33.5
33.4
20
35.7
35.3
35.2
50
38.2
37.6
37.6
100
40.0
39.4
39.3
200
41.9
41.1
41.0
500
44.3
43.5
43.3
1000
46.2
45.2
45.0
2.3.4.1
Exercise
Re-analyse the annual maximum gust wind speeds for East Sale for the years 1952-97,
i.e. ignore the high value recorded in 1998. Compare the resulting predictions of design
wind speeds for (a) 50-year return period and (b) 1000-year return period, and comment.
2.3.5
General penultimate distribution
For extreme wind speeds that are derived from a Weibull parent distribution (see Section
2.5), Cook and Harris (2004) have proposed a 'general penultimate' Type I or Gumbel
distribution. This takes the form of Equation (2.15):
