Need structural engineering help.....

[JTB]

New project beginning, garage extension. The overhang attached to the garage is going to become an additional 24' by 17' garage. The overhang is supported off the main garage by a steel beam which is supported at one end by a 6"*6" post and at the other end by a 6"*4" post, both set in concrete footings at the garage floor base. The steel beam is also attached to 4 off, 4"*4" posts which run from the roof joist to the garage floor also. When I remove the siding between the original garage and what will be the new addition I would like to remove the 4 off 4"*4" posts from the steel beam to the floor to give a full walk through access between the two working areas. Any comments if it would be safe to remove them? I have attached a number of pictures, if anyone needs any other info to help with an answer please ask......
Regards, John

 

[Charles (in GA)]

I suppose you don't have any snow loads to worry with. That roof looks so flat its a wonder any water drains off of it.

the existing building is a pole shed from what I can see of your pics. I don't see any way you can cut four of the poles on one side and still have any roof support. I doubt that steel beam can be used over that much span to support it and the shed roof too, but that is why you need a structural engineer........... who is probably going to tell you no way.

Charles

 

[6768rogues]

If you take the dimensions to a good lumber yard, they can have a wood microlam beam manufacturer run the calculations. You might need something like 2 or 3 fairly large microlams well braced laterally, but you should not guess. Microlam providers do this all the time.
You also need good solid posts and footings on the ends. And, in the process, you will need to shore up the roof to hold it while you rip out the wall and install the beams.
I once built a 24 foot wide by 14 foot deep porch with no center posts in the 24 foot span, in snow country. The beam manufacturer said I needed 3-14 inch deep 1 3/4 wide beams, and it never sagged a bit and had no noticeable deflection when walking on it.

 

[CraigFL]

As a structural engineer and a PE, I can tell you that there is always a way to do it. Without detailed calculations, what I would consider is to stiffen the WF beam spanning the four 4X4 support columns. Since the stiffness of a beam is proportional to the depth to the fourth power, this means you would only have to increase the depth about 50% to make it 5 times stiffer which should cover the removal of the four columns. There is one more consideration that needs to be made but I can't tell from your pictures if it's necessary -- lateral torsional buckling support. This consideration is necessary to keep a long unsupported beam from swaying to the side. It seems from your picture that the beam may be 6" in depth-the same as the 6"column but I can't tell for sure. It would also be nice to know what kind of beam it is.