Load Bearing Wood Stud Walls not under Walls 4

[canstruct]

Hi Guys,

I am designing a 3 storied wooden house. Problem i am getting is this that the walls from 2nd flr to roof are not lying under the walls below. Almost all the walls are off center and i am having difficulty in designing the floor at 2nd floor level. Can i distrubute the load coming from 2nd flr wall on the roof of 1st flr as partition. I am worrying how it could work in lateral loadings. Floor construction is TJI joists and wood stud walls. Only a small stretch in either direction is continuous which can't be resisted by wood shear walls. Can somebosy helps me in this case if all the walls are not in one plane and the they are supoorting load bearing walls.
Thanks and appreciayt if somebody can help me.

 

[msquared48]

The answer to your question lies in basic structural framing techniques. What is your current profession?

Mike McCann
McCann Engineering

 

[canstruct]

I am a structural designer in an engineering company in Toronto and designing a wooden house. I know it depends on the basic framing of the house. Actually this is 3 level house. Upto 2 levels it is fine, we have framed some beams at ground floor level to take the load bearing walls from ground to second.But it would be fine if they are in line. We have very few walls in line from top to bottom, even exterior wall have the same case.
Thanks

 

[msquared48]

You will have to put in a series of transfer beams to take the load from the bearing walls. May have to be steel if you want flat ceilings.

Mike McCann
McCann Engineering

 

[canstruct]

Thanks Mike,

Can we have an offset for load bearing walls on upper
levels and how much or we must have to provide transfer
beams in all cases. As far as non load bearing partitions according to Canadian Code, it can be offset max 2 ft from walls below.

Atif

 

[msquared48]

You could, but depending on whether or not you are using the same walls as shear walls, it could predicate extra beams in the joist space to transfer the holddown forces.

You will have to check the floor joists to make sure then can transfer the shear to the beam/wall.

Just remember 'KISS"!

Mike McCann
McCann Engineering

 

[dik]

You can also have the floor joists pick up the upper bearing wall if the loads are relatively small and the offset to the wall below is slight. You can also use parallam, wood I's or LVL type floor joists if need be.

Dik

 

[csd72]

Canstruct,

It is important to note that your internal walls do not need to be load bearing unless the joists cant do it in a single span. Your internal walls would then become partition loads as you stated.

The roof trusses should be supported at two points only as three points of support can have issues with lack of alignment of the wall tops.

Make sure you put posts or double studs under the ends of beams where necessary. You need to work these loads all the way to the foundation and provide more posts/ double studs in the lower floors as necessary.

csd

 

[AlmostPE]

Hah! Darn architects! They usually do this so they dont exceed the bulk plane. Or because some architect is really good on not stacking the walls. Well, design the joists to take point load from the roof. Also you need to put blocking between joists underneath the wall. I would put at least double 2x blocking. If the joists cant handle it, then you just have to put a beam underneath the wall and find a wall to put columns.

 

[dik]

AlmostPE's invective about Architects has some merit... You might talk to the dude and see if he can line things up a little better, explain to him that you are having some difficulty in sizing members due to the offset...

Dik

 

[whyun]

What I've witnessed in the past is one dude (architectural designer) laying out one level and another dude laying out the other completely independent of one another and the architect of record does not mediate.

Enough architect bashing for today... for me.

 

[AlmostPE]

What gets me the most is when they put trusses not spanning all the way to exterior wall. They bear it on interior wall that doesnt stack below.

 

[msquared48]

I always thought the word Architect was a euphemism for "Archaic Technology"...

Mike McCann
McCann Engineering

 

[csd72]

This is why whenever I get a new project, the first thing I do is look through the drawings for this type of thing. I then will make polite suggestions to the architect on minor changes that will 'save the client money'.

The earlier you make these suggestions the more likely that the architect will accommodate them.

csd