concrete floor over post set portal frame?

[desbromilow]

G'Day,

One of the shed options for construction is to erect the portal frames with the columns set in concrete.

My original design (designed by a structural engineer) is based on a bolt down construction and the slab has a number of beams, and slab thicknesses changes based on areas designated for machines, versus general use.

Is there any advantage using the post method?
If I have to use the post method, can I still get my slab poured with the beams, and varying thicknesses?

Anyone got any experience with roll formed type shed conctruction using a bolt down frame instead of a post set method?

Thanks,
Des

[Enfield Guy]

Gidday

Bolt down method would be my preference. I've built dozens of portal frame buildings this way, some as large as 2000M2.

Setting the posts in concrete would take away options. If you set the posts in concrete and it moves out of plumb during the pour it will then remain out of plumb.

My method of bolting down uses chem set bolts and half nuts under the posts to act as jacking nuts. This allows adjustment of each post. When the frame is up pack structural grout under the post plates.

Quicker, easier, better.

Cheers

[artme]

Have to agree with Bevan.

Look at how all the big industrial hangers are built and there is your answer.

[specialist]

Give the shed plan to the concreter and if he's any good He will be able to set bolts into the slab where the columns are to be placed. This is a common practice here. I have erected a number of sheds where this is the case with little or no problems.

Rob

[Enfield Guy]

I agree with Rob, but I do prefer to do the set out myself rather than rely on the skills of concretors. You wouldn't give the plans to these jokers. http://sfglobe.com/?id=969&src=share_fb_new_969

Cheers

[DaveTTC]

Not sure what thickness slab you are going etc but I would consider thickening the entire slab then if things are moved or repurposed you are not stuck with the original lay out

either build system works each with advantage and disadvantage.

Pouring to your sheet walls means it is sealed and no need of form work.

Slab first gives you flexibility as already noted. Frames should not be knocked out of plumb during slab pour but anything is possible


Dave the turning cowboy

turning wood into art

[Enfield Guy]

Pouring to the sheeted walls will cause the sheet in contact with the concrete to rust within ten years. I love it when people use that method. Makes for a very costly repair.

[DaveTTC]

I line mine with plastic which means the seal is not as good. I have considered painting with tar?


Dave the turning cowboy

turning wood into art

[desbromilow]

slab (as currently designed) is 450 x 450 at all edges and beams, 150mm thick under 1200 strip along each side of the shed (where benches/big tools go) and 100mm thick through the remaining width of a 6m wide shed

The floor will have elephant foot ferrules installed in each beam along the shed centreline for creating anchors to 22T shear pull, 5T axial pull.

I have toyed with 150mm thick all over, let's see how many pennies I have left after finding someone affordable to supply the materials.

I want to avoid pouring to the sheet because of the known rust issues. I plan on using expanding foam, or bitumen impregnated foam sealing strips for the concrete/tin join at the floor

Thanks,
Des

Not sure what thickness slab you are going etc but I would consider thickening the entire slab then if things are moved or repurposed you are not stuck with the original lay out

either build system works each with advantage and disadvantage.

Pouring to your sheet walls means it is sealed and no need of form work.

Slab first gives you flexibility as already noted. Frames should not be knocked out of plumb during slab pour but anything is possible


Dave the turning cowboy

turning wood into art

[Enfield Guy]

Expanding foam is the best bet I reckon. I mostly use the Sika Fire rated stuff.