Wood as wind girt? 3

[palk7 EIT]

Hi,
In order to have infill studs beneath a wide opening 20' could wood beams on flat (multiple) be used as a girt as attached in the pic, since clip angles are used at every stud to this girt could the span for analysis of this girt be reduced to the spacing of studs or the span has to be considered 20 feet as that of between the col's. Max. trying to avoid using a steel girt here. This 3' height infills are creating hinge as it is being added to exist. structure. Any advice?

Thank you!

 

[BAretired]

Span is 20', a long span for a 5.5" deep LVL. Check stress and deflection. Why would you think it could be reduced?

BA

 

[JAE]

I think what you are suggesting is that the little clips on the small studs would somehow "fix" the studs such that they are cantilevering off the floor and helping the sill beam.
I don't think this would really happen.

The beam would have to span the 20 ft. and take its share of the wind load from the 1/2 stud height below and whatever window span occurs above.

 

[palk7 EIT]

Yes I thought if those clips help in fixing the studs there, yeah I need to check for the full span.

 

[palk7 EIT]

Should Wind loads be factored by 1.5 like a Live load?

 

[JAE]

Depends on the code and the design method you are using. In my neck of the woods (US) I've never factored live loads by 1.5.
For wood design I use ASD which provides for allowable stresses in wood members and connections. There is no load factor on that.

Can you explain a bit where you got your 1.5 factor? Is this a Canada code?

 

[BAretired]

Use factored loads for strength check, unfactored loads for deflection check.



BA

 

[BAretired]

JAE,
The Canadian code uses only one method of analyzing structures. We called it Limit States Design in my day, but it may have a different name now. The load factor for live load, including wind was 1.5. There is no longer a Working Stress Design (WSD) permitted in the Canadian code.



BA

 

[palk7 EIT]

Yes, agree with BAretired

 

[BAretired]

palk7,

The notion of using 3' long studs, fixed at the base is not wrong, provided that the rim beam is capable of resisting the applied moment, but you cannot use little angle clips to attach them at the base. Developing moment connections with conventional wood framing is possible but is not commonly done.

BA

 

[palk7 EIT]

O.k, just to know, what is the role of infill studs is it there just to stiffen the exterior sheathing or does it act as a transfer medium to transfer the wind pressure to the girt?. If it helps to transfer then, that connection point of the stud to girt (above) or the stud to the bottom plate which in turn is connected to rim joist +LVL below must be designed for a horizontal point load at that connection so in that case would that point load be the spacing of studs * height of exposure?

 

[KootK]

O.k, just to know, what is the role of infill studs is it there just to stiffen the exterior sheathing or does it act as a transfer medium to transfer the wind pressure to the girt?

The infill stud perform both of those functions.

If it helps to transfer then, that connection point of the stud to girt (above) or the stud to the bottom plate which in turn is connected to rim joist +LVL below must be designed for a horizontal point load at that connection so in that case would that point load be the spacing of studs * height of exposure?

Yeah, each infill stud would deliver a little reaction, top and bottom equal to [height/2 x spacing x design wind pressure]. For your girt span and stud spacing, most engineers would just approximate all those point loads a uniform, lineal load equal to wind [height/2 x design wind pressure] to the girt and the diaphragm below.