Wind Load Calculator

I've started recently working on a wind load calculator.

Notice the complexity when overhangs are added to the roof. These load diagrams show the Envelope Procedure for a Gable Roof:

Load Case A:









Load Case B:





If torsional load cases are required then another Load Case A and B are required for the torsional load case.

Interesting to note that for a gable roof only the wind forces on the walls contribute any lateral forces to the roof diaphragm and then to the shear walls for the longitudinal direction (wind parallel to ridge).

The breakdown of the forces would then be:

Transverse:



Longitudinal:



One could argue that there is a certain amount of wind force on the edge of overhangs but I'm thinking its insignificant.

Shearwall reactions are now complete, assuming of course that only the exterior walls are acting as shear walls. This assumption is pretty useless for building with dimensions exceeding a certain limit since they will probably involve steel moment frames or multiple internal shear walls. I'm wondering if it might be useful to add some sort of advanced option which lets one specify an internal shearwall spacing or even a internal shearwall layout. The programming would get pretty complex.

I also added the ability to calculate truss/rafter uplift and horizontal load. Not entirely sure how useful this is either but I've personally ran into it enough times so I thought it might be of some benefit. The funny thing is after writing the code and creating the image for this section (3) I happened to look at a truss manufacturer's output for a garage I was designing a while back. I quickly noticed that the horizontal reactions and uplift were listed on the document, so if you've already taken your design to get the trusses quoted you probably don't need this information calculated. Just out of curiosity I used the same parameters as the truss manufacturer used for their wind loads and after adjusting for the TC and BC dead loads both my horizontal reactions and uplift were within 0.5 lbs of their values. Nothing like a third party check nailing it so perfectly, that is why I love this stuff.

Looks nice and fancy, how long did it take you?