Bldg design for 4 stories. 1 was built. Can I rotate colmn. on 2nd?

[dassouki]

Sorry for the short title as it is limited in Number of Characters.

I do some building design on the side, here is the situation:

* According to the design plans, the building was built for 4 stories (1+3).
* I'm designing the second floor right now, however, I'd like to rotate some of the columns from the Main floor
* Actual floor plan and proposed second can be found under

http://97.107.136.148/plan_1_and_2.pdf

The columns, I'd like to rotate are the ones within the zigzag circle. On the plan is the beam layout as well

Is this possible? Any other solutions I can look into?

cheers, and thanks in advance

 

[dassouki]

As a note, the first floor is built, I'm designing the second floor layout and not structural elements. I just wanted to make sure before presenting this plan that it is actually potentially doable

 

[frv]

What do you mean when you say you do "building design"? Do you men interior finish-out or structural engineering?

 

[dassouki]

@frv - Space layout. I haven't really worked with Concrete based structures before. I'm just organizing the space upstairs to fit two apartments.

 

[TomasAron]

I think anything is possible. But will the owner want to spend the money. You might have to dig out the foundation to accommodate the new layout. And then the structural engineer may have to design new connections. I would say it's a lot of work to move these columns. There are a lot of variables.

 

[frv]

OK. I was about to rip you a new one because your original post made it sound as though you were practicing structural engineering without knowing what you are doing.

Simple answer: maybe. Get a Structural engineer involved and tell the owner it will cost money to change it.

 

[dassouki]

@frv, I've been in traffic and transportation engineering for 4 5 years, but before that and during was designing "architecturally" buildings and laying out space. I'm looking to fully transition to structural within the next year or so, just trying to find employment that'll take people like me (experience in other aspects of Civil but not in structural). Currently, I'm going through the building code of Canada, and trying to calculate the loads on some buildings, dead, live, seismic, wind, and rain. After that, I'm going through the steel and concrete manuals to start learning how to design structures. I'll be doing that until I can find a structural engineer so i can practice under. For now, I'm learning structures for myself and not applying on any real world projects.

 

[dassouki]

@ThomasAaron : I agree about involving a structural, but for now, I'm just drawing up options. I have the diagrams for the footings; however, I don't know nor do i want to venture in calculating them. I'm drawing up the plans to give the client options that they can decide on.

 

[TomasAron]

Well if it is just layout then I would give the proposed layout to the client with the understanding that this will have to be checked structurally.

 

[BAretired]

If the first floor is built, there must be a structural engineer of record. Why don't you ask him whether or not it is doable? My guess is he will say no.

BA

 

[csd72]

Looks to me like this would be difficult and expensive, maybe the layout should have been firmed up prior to starting construction!

If I was the engineer and I got asked by anyone but the client, I would tell them where to go. Probably still would tell the client the same thing.

 

[dassouki]

@csd72, the house was built 25 years ago. According to them, they built the house so they can extend it upwards later on.

 

[csd72]

Ah, the plot thickens.

Can you provide more information on the structure.

 

[dassouki]

@csd72 and others: Foundation plan:

http://97.107.136.148/scan321.pdf

 

[dik]

For a 4 storey building, the column loads should be relatively light and it may be possible to rotate columns. They would have to be checked for bearing, load transfer through the floor plate, and eccentricity; if these are not an issue it would be fairly easy. The original engineer should be contacted and do the revised design. I did a 20 storey office bldg in Winnipeg about 40 years ago, where the client wanted to move one of the main building columns about 6'... and it took a couple of storeys to transfer the load... foundations had already been constructed.

Dik

 

[dassouki]

@dik , New Brunswick says Hello! The first is constructed right now, and they're only going to go ahead with a second story, and nothing higher, as new building regulations in that country will not allow them to go higher than 2.

 

[racookpe1978]

Given that the problem seems to have been aborted by the 2-story limit, if the 2nd floor were not yet poured or built, then couldn't a flat plate be inserted between the column steel - at the concrete floor level of the 3rd floor - then the column could be rotated, right?

Example: Usually, columns are two stories high, geting smaller at every other floor. The "usual" columns penetrate the floors, and are connected (spliced) to the next column higher about 24 - 36 inches above floor level.

So, if you want to rotate the column for some reason, you can't really rotate at the splice point since the lower and upper webs and flanges won't line up, but you have to do it where the connection won't stick out into the usable working areas of the building. So I'd think you could cut off the column coming up from the 2nd floor near the floor level of the third floor (below the concrete), then weld a heavy pair of plates in position to carry the forces through the joint, then continue up to the next splice point with the upper column rotated from the lower.

Where is my thinking wrong? Expensive, true, but is it wrong structurally?

 

[BAretired]

On the basis of the latest information, it appears quite doable. It is possible that the columns could even be reduced in size.

BA

 

[hokie66]

It's the "According to them" which needs to be resolved. Now is the time to get a structural engineer retained, either the original one or somebody else.

 

[csd72]

There is one big concern that I have here and that is the lateral stability system. It looks to me like the blade columns may be used as part of a concrete moment frame to resist lateral loads. If this is the case then I cannot see an east way to rotate the columns. If there is masonry infill being used for lateral stability then there may be other options available.

We do not have enough information on this forum to give an accurate answer, only the original designer is able to do that.