Steel structure to support slats.

[Hirdy]

I’m tanking a group level shed, 4ft deep and 72ft x 48ft, to install plastic slats for sheep. I need to construct support for the slats

My contractor has quoted 28k to supply and install a galvanised steel mezzanine style structure using:

Posts - 254 x 146 x 31 UB
Beams - 254 x 146 x 31 UB
203 x 133 x 25 UB

This seems really overkill considering the slats are supported by fibreglass beams supplies by the manufacturers.

My contractor has assured me that using concrete pillars would cost just as much.

Does anyone have any idea how to go about this without remortgaging the house? How can I calculate the steel requirements myself?

Any guidance is greatly appreciated

 

[johnpeels]

There is not enough information in this post to give a meaningful reply. How long and what spacing are the fibreglass beams? The beams do seem massive at first sight? Presumably there is to be grid of beams, let us know the x and y spacing dimensions of the grid, and then we can see if the beams are overkill or not.

 

[Hirdy]

Yes, i was a bit vague. thanks for your reply

The slats are 800 x 600 mm. The fibreglass beams are 800mm apart. Please see photo. And are 150mm high and 29mm wide and need supporting every 2.4 metres.

The contractor has not provided a plan as of yet,. But I expect the grid to be of beams to be 5m x 5m supported by posts with a secondary beam running north to south to support the fibreglass beams. I've attached a plan.

 

[mezz]

You don't need a grid, just 5 rows by 72 foot of steel running parallel, because the fibre glass supports are only 8 foot long.

I would advise against using steel beams a slurry environment can be very corrosive, concrete would be much better.

All the tanks I have done the pillars have been done with 6" blocks, made 18" square. Some of the beams were done with single cattle slats, about 10' long I think. Using single cattle slats is frowned upon nowadays as not strong enough, but the original tank is in about 35 years trouble free. The newer tanks have purpose made beams about 10-12” square.

How are you planning to feed with a shed that size? Looks like feed space would be tight even if feeding on all 4 sides?

 

[dave mountain]

i think the contractors spec is about right. concrete would be cheaper in material but more expensive overall, and is a pain in the arse to do anything with.

i think you are overlooking quite a lot of things. the beam sizes are about right for the loading expected, and yes the posts are overkill but it makes it a lot easier to put together if the beams and posts are the same.

28k isnt out the way for that work in the present economic climate.

 

[newhollandfarmer]

Where are you based? I have done a few of these.

 

[concrete agri]

 

[concrete agri]

Thats one we done for plastic pig slats

 

[shumungus]

The standard support over here for plastic sheep slats is very simple. If it has to be removable for cleaning out semi solid use 4"or6" sewer pipe freestanding on its end individually cut to length for the correct height and numbered for easy replacement. If its going to be a mixed tank of slurry use 6" sewer pipe drill a couple of rebars into the floor in the centre of the pipe and fill with concrete, simples. You don't need a beams you just need support columns at each fibreglass join. The steel frame thing is nonsense and Steel should never be below slats of any type.

 

[Hirdy]

Thanks. So…what the contractor is proposing priced about right but not necessary. @concrete agri and @mezz approach will work - 24 concrete posts and beams, but as @shumungus says I can make it even cheaper by not having beams and instead 46 concrete posts. 2 rebars per post, but what strength concrete? And how far to drill down for the rebars?

@mezz I'm planning on splitting it into 3 pens with adlib concentrate feed running down the rows between pens and on the outside walls.

 

[dave mountain]

Thanks. So…what the contractor is proposing priced about right but not necessary. @concrete agri and @mezz approach will work - 24 concrete posts and beams, but as @shumungus says I can make it even cheaper by not having beams and instead 46 concrete posts. 2 rebars per post, but what strength concrete? And how far to drill down for the rebars?

@mezz I'm planning on splitting it into 3 pens with adlib concentrate feed running down the rows between pens and on the outside walls.

if doing it in concrete you would be far better with the 46 posts. the required beams would be very heavy otherwise. beams will need to be pre-stressed beams/lintels, they are cheap as chips. for everything else i would go C30/C35 as the cost isnt much more than a basic foundation mix.
if there is an existing concrete base drill as far as you can through it without penetrating the other side, and set the rebars in using polyester or vinylester resin. then put your pipe around and fill with concrete.

if the existing conrete base has no reinforcement you will probably have to dig out a hole and put an new pad in for every post, or the point loading from the slats above will break the existing pad.

 

[Hirdy]

My post was full of typos and unclear...make it even cheaper by having concrete beams and more concrete posts.

Thanks Dave. What span prestressed beams could sit on 6" concrete posts?

 

[shumungus]

Have you asked the outfit supplying the slats as to what they recommend or spec?

 

[dave mountain]

My post was full of typos and unclear...make it even cheaper by having concrete beams and more concrete posts.

Thanks Dave. What span prestressed beams could sit on 6" concrete posts?

personally i would want the posts bigger than 6", gives you more area on top to rest the beams on and more surface area at the bottom for the load to be spread across. could use some 300mm twinwall pipe or even some sch10 pipe to fill with concrete. if you use twinwall make sure there is enough rebar in it. if you use sch10 you wouldnt need any rebar other than at the bottom to hold it in place

the limiting factor for span is likely to be what the posts are resting on unless they are on proper pads

 

[Dyffryn]

 

[Hirdy]

@Dyffryn what size beans and columns did you use?

 

[Dyffryn]

Its all 7’x3’ i think.

 

[JeremyD]

@Dyffryn what size beans and columns did you use?

If you are interested I have alot of plastic slats for sale with or without galvanised steel support bars. They are made by MIK all excellent condition were removed from our pig buildings recently and were not very old when removed. @Hirdy

 

[Fatlamb]

If you are interested I have alot of plastic slats for sale with or without galvanised steel support bars. They are made by MIK all excellent condition were removed from our pig buildings recently and were not very old when removed. @Hirdy

Could you send me the details please?

 

[Hirdy]

Its all 7’x3’ i think.

I guess that is a beam of 178 x 102 x 19, which is much smaller than what my contractor is suggesting. I’m only going to 1.2 metres in height too. This is really frustrating