Civil Engineering Reference
In-Depth Information
The data in ISO 4354 (non-rectangular buildings) are quite old and pre-date
boundarylayer wind tunnels. The data in the other documents appear to be based on
modern wind-tunnel measurements for the most part. prEN 1991-1-4.6 clearly contains
the most comprehensive set of data.
15.9
Dynamic response calculations
The first five standards contain procedures for the calculation of dynamic response for
wind-sensitive structures such as slender, flexible, lightly damped tall buildings. ASCE-7
and AS/NZS 1170.2 classify wind-sensitive structures as those with a first-mode natural
frequency less than 1 Hz; ASCE-7 also requires a height to breadth (or depth) ratio
greater than four. ISO 4354 considers a structure slender if the height to diameter ratio
exceeds six.
Figure 15.6
Comparison of pressure
coefficients for a domed roof (main structural
loads),
h/d=
0.2, rise/span=0.2.
