topic Wind loading on angle and round members using Robot wind generator in Robot Structural Analysis Forum

Wind loading on angle and round members using Robot wind generator

barryc — Fri, 23 Mar 2018 07:22:20 GMT

I have calculated my wind pressure at 10m above the ground, edited the wind profile for elevation and have noted that the wind pressures does not change for members with sharp corners (angles) and round members (pipes). As the wind on an angle has a Cf factor of approximately 2.0 and approximatly 0.7 for round members. I have selected the round members in my structure and generated my wind loading for those elements and the done the same for my angle members. When combining the wind loads in the combinations I have applied a Cf factor of 0.7 for the load cases with round elements and a Cf factor of 2 for the angles, beams and channel members. This again if multiplied by and ultimate factor of 1.3 for wind loading. The ultimate factors maybe different depending on your design code. Is this approach the norm or is there a better way?

Re: Wind loading on angle and round members using Robot wind generator

Artur.Kosakowski — Fri, 23 Mar 2018 09:11:28 GMT

Hi @barryc

The wind simulation replaces the exact shape of the profile with the rectangular shape 'based' on its 'outer' corners while running the CFD analysis. As the generated wind load doesn't include any load factors they should be introduced for ULS combination types but I'm not sure if you should use Cf factors with the values as you described them. IMHO you may consider using the 'reduction' factor for pipes but I'm not sure if you should increase the load values for other.

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Re: Wind loading on angle and round members using Robot wind generator

barryc — Fri, 23 Mar 2018 11:59:21 GMT

Hi Artur,

Many thanks for your reply.
Square rectangular sections with rounded corners the factor would be approximately 1.0: thus providing the forces by Robot.
According to design most design codes members with sharp edges (angles) have a larger wind load while members with rounded corners will have a lower wind force for the same width.
I will apply the code factors to increase the force for angles (2.0 factor) and a reduction factor for round members (0.7 Factor).

Many thanks for help.