NZS 1170.2 Wind actions

Building are classified by importance level (IL) depending on their use.

What is the importance level of the building we are in at the moment? (Tables 3.1 and 3.2 of NZS 1170.0)

• IL 1

• IL 2

• IL 3

• IL 4

The usual design life for a new building is _________ years.

So, the design wind event for this building has an annual probability of exceedance of ______________ (Table 3.3 of NZS 1170.0).

Dunedin is in wind region ___________ so the regional wind speed for an A.P.E. of 1/500 is _______ m/s. ( ref NZS 1170.2 )

The design wind direction multiplier (M_d) varies according to the critical wind direction. In Dunedin, an easterly wind direction could have an M_d value of

(select all that apply)

• 0.8

• 0.85

• 0.9

• 1.0

For wind from the west, what is the terrain category for the building we are in at present?

Justify your answer using clause 4.2.1

The height of the eaves above ground level is 3.6 m. The ridge is at a height of 5.6 m. Use Figure 2.1 to determine the value of 'z' for use in Table 4.1

• 3.6 m

• 4.2

• 4.6 m

• 5.6 m

Calculate the value of M_z,cat for a building with height (z) of 4.6 m in terrain category 1.

• 0.99

• 1.02

• 1.04

• 1.05

Calculate the wind pressure due to a 35 m/s (126 km/h) 3 second wind gust velocity. Use clause 2.4.1 of NZS 1170.2

• 735

• 735 Pa

• 735 kPa

• 735 N/m²