The Structural Engineer's Corner

Eng. Onorio Francesco Salvatore

Archive for the 'Wind actions' Category

Coefficient of exposure for wind action – Difference between ISO 4354 and AS/NZS 1170.2


The Australian Standards adopt in many parts recognized International Standards. For what regards the Wind Action the reference is the ISO 4354 “Wind action on structures”. One of the differences between the AS/NZS 1170.2 and the ISO 4354 is the exposure factor Cexp. The Australian Standard decided to not adopt that factor because it has […]

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Excel spreadsheet for the evaluation of the Dynamic Response Factor as per AS 1170.2


As announced in a previous post (The Dynamic Response Factor as per Australian Standard 1170.2), I’m putting on free download an Excel tool I just created for the evaluation of the Dynamic Response Factor as per Section 6 of the Australian Standard 1170.2. The inputs needed are the following: Design wind speed for chosen direction; […]

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The Dynamic Response Factor as per Australian Standard 1170.2


In order to evaluate the design wind pressure on a structure, the basic pressure has to be multiplied by an Aerodynamic Shape Factor (as per Section 5 of Australian Standard AS 1170.2) and by a Dynamic Response Factor (as per Section 6 of Australian Standard AS 1170.2). The Standard specifies that the value of the […]

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Orientation factor in wind action evaluation according to Australian Standard 1170.2


Once obtained the Site wind speed, the Structural Engineer needs a Design wind speed. As said in previous article, the Site wind speed – as the name says – is only related to a specific site, no matter of what structure we are analysing. In order to evaluate the specific wind speed on structure, the […]

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Factors affecting the Site wind speed in Australian Standards


In the previous article we have discussed about the Site wind speed. It is independent of the structure shape and has to be seen only as a wind speed characteristic for a specific site. In fact, to determine the Site wind speed, the Structural Engineer takes the Regional wind speed and multiplies it by some […]

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Corrective factors for uncertainties in wind action calculation


In the previous article we have talked about the Regional wind speed and we have seen as this value is function of an additional corrective factor for tropical cyclones regions C and D. This factor is included to allow for uncertainties in the prediction of ultimate design wind speeds for those regions. Structural Engineering often deals with 

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Site wind speed according to AS/NZS 1170.2


In order to obtain the Design wind velocity, the Structural Engineer needs to define the Site wind velocity. This value is substantially defined as the Regional wind velocity modified taking into account the direction and the exposure of the site. The formula used is: Md is a wind directional multiplier for the 8 cardinal directions […]

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Regional wind speed according to AS/NZS 1170:2


In order to obtain the design wind speed to be used in the calculation of design wind pressure, a regional wind velocity and a site wind velocity must be calculated. VR, the Regional wind speed, is defined as a 3-second gust wind speed. It is an all-directional basic action because no considerations on direction from which wind gust is […]

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