AS4055 Racking Force

[Engineering05]

Hi All,

I have begun the process of design my first timber framed house. In doing so I have relied on AS4055 (wind loads for housing) for the determination/calculation of racking forces.

I was hoping to have someone with experience in the use of AS4055 to answer why this code stipulates that we multiply the tabulated wind pressures by only one projected area. This does not make sense to me because in the appendices they explain that the tabulated wind pressures are derived by adding windward & leeward/upwind & downwind aerodynamic shape factors to give a total shape factor. Why are we not instead multiplying the tabulated wind pressures by both the windward and leeward projected areas (or, generally 2 x projected area)?

 

[rowingengineer]

there is nothing stoppong you from checking with as1170 and basic areas including force resultants

http://www.nceng.com.au/

"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning."

 

[asixth]

AS4055 is written such that racking loads are calculated by applying a net pressure over the area of elevation. I've back calculated the racking force using windward and leeward pressure coefficients from AS1170 enough times to feel comfortable with the approach.