Steel Beam into Cavity Wall without pillar?

[RonnyRaygun]

I'm not really au fait with anything other than simple structural masonry design, mainly because where I work we almost always put frames or piers in when removing walls, and leaving lengths such as shown on your drawings without such lateral resistance isn't something we would ever do.

However, I believe your engineer's thinking goes something like this:
She is taking the view that the masonry is spanning vertically between the floor and ceiling, and is therefore restrained top and bottom. Joists are spanning in the wrong direction to give restraint so she must be ensuring the floor and roof are both well strapped to the wall (which they should be).
This assumes that the floor and roof are both stiff enough to distribute loads to the shear walls.
However, you've got limiting dimensions for wall panels, and you've also got some window and door openings breaking up the wall in the horizontal direction, so the windposts are there to give restraint in the horizontal direction.
The windposts under the 254 UC are there to deal with the lack of restraint at the first opening.
The windposts under the 203 UC are probably there to help with the minimal restraint where the new wall meets the existing...

I'm sure your engineer has considered the wall's stability and is happy that there is nothing to worry about. But ask her and let us know what she says. I'm interested in her answer and might learn something!

Deanomy might come back and give a better explanation...

 

[geraint]

I'm not really au fait with anything other than simple structural masonry design, mainly because where I work we almost always put frames or piers in when removing walls, and leaving lengths such as shown on your drawings without such lateral resistance isn't something we would ever do.

However, I believe your engineer's thinking goes something like this:
She is taking the view that the masonry is spanning vertically between the floor and ceiling, and is therefore restrained top and bottom. Joists are spanning in the wrong direction to give restraint so she must be ensuring the floor and roof are both well strapped to the wall (which they should be).
This assumes that the floor and roof are both stiff enough to distribute loads to the shear walls.
However, you've got limiting dimensions for wall panels, and you've also got some window and door openings breaking up the wall in the horizontal direction, so the windposts are there to give restraint in the horizontal direction.
The windposts under the 254 UC are there to deal with the lack of restraint at the first opening.
The windposts under the 203 UC are probably there to help with the minimal restraint where the new wall meets the existing...

I'm sure your engineer has considered the wall's stability and is happy that there is nothing to worry about. But ask her and let us know what she says. I'm interested in her answer and might learn something!

Deanomy might come back and give a better explanation...

if you are not au fait..... you cannot commnet

and you were trying to prove that you were an engineer

so what is a basic structurall masonary design....

 

[RonnyRaygun]

if you are not au fait..... you cannot commnet

and you were trying to prove that you were an engineer

so what is a basic structurall masonary design....

I thought you'd be back troll boy

The difference between you and me is that I am happy to learn from people who know more than I do...the reason you know nothing is that you think you know everything...

 

[theoldun]

so what is a basic structurall masonary design....

Not taking the p**s or having a dig, but we would class it as being a brick or stone built building, from a shed to a cathedral. Other folk may think differently.
oldun

 

[GeorgeWBush]

But ask her and let us know what she says. I'm interested in her answer and might learn something!

Yes, of course. That's the very least I can do for all the help I've had on here! I'll post as soon as I get an explanation.

 

[geraint]

if you are not au fait..... you cannot commnet

and you were trying to prove that you were an engineer

so what is a basic structurall masonary design....

I thought you'd be back troll boy

The difference between you and me is that I am happy to learn from people who know more than I do...the reason you know nothing is that you think you know everything...

still waiting for an answer to your previous post

have you lost the balls beneath..

or just a jo boy....

 

[geraint]

and still waiting jo boy.........

 

[GeorgeWBush]

I've had the following response from our SE with regards to the source of lateral stability in the design. Once again, would be very greatful for your thoughts.

"A portal frame could be used to provide lateral stability. However as you have already installed the foundations and sleeper walls this would involve a significant amount of breaking out work. We have therefore chosen an alternative solution that utilises cross walls and floor diaphragms and avoids the need for altering the existing new foundations.

The lateral stability is therefore provided by a horizontal diaphragm created from the ceiling over the single storey extension (see section E-E drawing 102b) and masonry return and cross walls throughout the rest of the building. Please note that we require the new wall to the rear of the ground floor bathroom to be constructed of block work as per our drawing 101b (bottom right corner of 101b)."

101b: View media item 31892 102b: View media item 31893

 

[deanomy]

Looks better, without doing the maths it would be hard to tell if shear walls are adequate, though the theory - diapragm walls etc sounds good.

 

[GeorgeWBush]

Thanks Deanomy.