Cutting door in existing tilt up panel at panel edge

[reviest54]

A client wants to cut a door 3'x7' in an existing 6" tilt up panel. I have done plenty of these but never one where the client wanted to cut the opening across the joint between two panels. In plane shear will not be an issue. Besides loading the two panels in question and figuring out a way to get the out-of-plane forces into the foundation and across the joint (most likely a steel frame), is there any other issues I am not thinking of?

Is cutting openings across panel joints a common practice? I have never run across it before.

Thanks

 

[racookpe1978]

How will your two panels behave they are tilted up?
Or will he cut the door opening once vertical? (and, we assume, fully supported against sway and wind loads across the joint?)
How will he prevent water/ice/snow/mildew damage getting down the joint into the door lintels and door itself? (Wood door or metal?)

 

[KootK]

It might be better this way. Losing 18" of a panel probably does next to nothing to its out of plane capacity. Might just need to restore connection to foundation at the cut edge. I don't se a need for a steel frame.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[hokie66]

I suspect that KootK is right. But a bit more information about the geometry would help. How wide are the panels? Will the door be centred on the joint?

 

[reviest54]

Thanks for the replies. I was worried about water in the joint as well. We don't have ice and snow here so that is not a concern. I have attached a sketch of the two would be affected panels. The door is metal. The opening would not be centered on the joint because of a partition wall the client does not want to demo at all.

I was thinking about suggesting to the client moving the new door near the existing overhead door leaving 18" or so at the end of the panel. Then I can treat as one large opening similar to how I have done in other openings in existing panels. He would have to move some conduit and switches to do that.

Any thoughts are appreciated.

 

[hokie66]

Now that you have given us all the information, my answer is different. On one side, you would be removing about half of the width of the leg, thus presumably half the capacity. I think your original idea of a vertical steel strongback is probably the best approach.

 

[spats]

I design lots of tilt-up, and I think it's generally a bad idea for a door or window to cross a panel joint. You will potentially have movement between the panels at the joint due to concrete shrinkage, thermal, etc. Such movement could cause problems with the operation of the door, and stress the door frame. I agree with Hokie that you're unlikely to get the reduced panel leg to work without adding a strongback. Keep in mind that if the strongback is not stiffer than the reduced concrete leg, the leg is likely to crack.

 

[reviest54]

Thank you all for your responses. I have suggested to the client to look for another area to create the door. There are two other walls that would be much easier structurally speaking. We shall see how it goes.

 

[msquared48]

I too agree with Hokie here.

Mike McCann, PE, SE (WA)