Tie down

I was asked a question the other day on "What tie down do I need". This is not a short answer. Tie down in construction is resisting wind uplift on a building.

1. The first thing is to determine the Uplift Load Area. Ask yourself how much area is this tie down holding down. Next you need the uplift force.
2. What is the force per sq m that is acting on the building. This can be determined by going to Australian Standard 1684. This standard will give you the uplift force based on the wind speed for the area (AS 4055) and the weight of the building being held down. So the uplift force on the roof / wall frame for a single storey dwelling located in a N3 wind rated area and with a sheet roof the uplift force is 1.33kPa.
3. Multiply you area and kPa to achieve a kN force. Say your area is 10 sq m then the uplift is 13.3kN.
4. Now you select a tie down connection rated at 13.3kN. Be careful to consider the joint group of the frame and the tie down capacity of the whole connection including the type of fixing into a concrete slab.

Easy.

For more info you can contact me at work

Local Planning Schemes

In my day to day work I need to reference the Local Planning Schemes to ensure I issue compliant building approvals. I have been using a good web site located in the Queensland State Government Dept of Infrastructure and Planning that has links to all of the local town plans in Qld. This has saved me time trawling through each local Government site. Enjoy